# Khanacademy.org how to use, tutorial

### Simplifying polynomials (video) | Khan Academy

**Details: **simply 3x squared minus 8x plus 7 plus 2x to the third minus x squared plus eight x minus 3 so when we simplify this we're essentially going to add up like terms and just as a reminder we can only add or subtract like terms or simplify like terms and just a reminder and what I mean by that if I had an x squared to an x squared these are like terms they're both x terms raised to the same power

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› Url: https://www.khanacademy.org/math/algebra-home/alg-polynomials/alg-introduction-to-polynomials/v/simply-a-polynomial Go Now ^{}

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### How to find area of triangle (formula walkthrough) (video

**Details: **Learn how to find the area of an obtuse triangle. If you're seeing this message, it means we're having trouble loading external resources on our website.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-geometry-topic/cc-6th-area-triangle/v/example-finding-area-of-triangle Go Now ^{}

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### Solving systems of equations by elimination (video) | Khan

**Details: **Let's explore a few more methods for solving systems of equations. Let's say I have the equation, 3x plus 4y is equal to 2.5. And I have another equation, 5x minus 4y is equal to 25.5.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/algebra-home/alg-system-of-equations/alg-equivalent-systems-of-equations/v/solving-systems-of-equations-by-elimination Go Now ^{}

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### Khan Academy | Free Online Courses, Lessons & Practice

**Details: **Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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› Url: https://www.khanacademy.org/ Go Now ^{}

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### Rewriting decimals as fractions: 0.15 (video) | Khan Academy

**Details: **Decimals can be written in fraction form. To convert a decimal to a fraction, place the decimal number over its place value. For example, in 0.6, the six is in the tenths place, so we place 6 over 10 to create the equivalent fraction, 6/10. If needed, simplify the fraction.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/arithmetic/arith-decimals/arith-review-decimals-to-fractions/v/converting-decimals-to-fractions-1-ex-1 Go Now ^{}

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### Multiplying and dividing with significant figures (video

**Details: **Now that we have a decent understanding of how to figure out how many significant figures we're even dealing with, let's think about a situation where significant figures will or might become relevant.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/arithmetic-home/arith-review-decimals/arithmetic-significant-figures-tutorial/v/multiplying-and-dividing-with-significant-figures Go Now ^{}

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### Systems of equations with graphing (video) | Khan Academy

**Details: **Sal shows how to solve a system of linear equations by graphing and looking for the point of intersection.

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› Url: https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-systems-topic/cc-8th-systems-graphically/v/solving-linear-systems-by-graphing Go Now ^{}

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### Area of trapezoids (video) | Khan Academy

**Details: **Area of a trapezoid is found with the formula, A=(a+b)/2 x h. Learn how to use the formula to find area of trapezoids.

› Verified *1 days ago*

› Url: https://www.khanacademy.org/math/basic-geo/basic-geo-area-and-perimeter/area-trap-composite/v/area-of-a-trapezoid-1 Go Now ^{}

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### Decomposing a fraction visually (video) | Khan Academy

**Details: **So let's think about all of the different ways that we can represent 7/9. So let's just visualize 7/9. So here I have 9 equal sections. And 7/9 you could represent as 7 of those equal sections.

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› Url: https://www.khanacademy.org/math/arithmetic/fraction-arithmetic/arith-review-decompose-fractions/v/decomposing-a-fraction-visually Go Now ^{}

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### Resonance structures (video) | Khan Academy

**Details: **Voiceover: Sometimes one dot structures is not enough to completely describe a molecule or an ion, sometimes you need two or more, and here's an example: This is the acetate anion, and this dot structure does not completely describe the acetate anion; we need to draw another resonance structure.

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› Url: https://www.khanacademy.org/science/organic-chemistry/organic-structures/formal-charge-resonance/v/resonance-intro-jay Go Now ^{}

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### Glucose insulin and diabetes (video) | Khan Academy

**Details: **Every cell in the human body needs energy to survive and do its different functions. If we're talking about a brain cell, it needs energy to keep stimulating other brain cells and sending on signals and messages.

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› Url: https://www.khanacademy.org/test-prep/mcat/biomolecules/hormonal-regulation/v/glucose-insulin-and-diabetes Go Now ^{}

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### Converting larger number from decimal to binary (video

**Details: **- [Voiceover] Let's now see if we can convert a larger decimal representation to binary. So let's say that we have the number 114 and this is its decimal representation.

› Verified *1 days ago*

› Url: https://www.khanacademy.org/math/algebra-home/alg-intro-to-algebra/algebra-alternate-number-bases/v/large-number-decimal-to-binary Go Now ^{}

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### Naming benzene derivatives introduction (video) | Khan Academy

**Details: **Naming benzene derivatives introduction. If you're seeing this message, it means we're having trouble loading external resources on our website.

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› Url: https://www.khanacademy.org/science/organic-chemistry/aromatic-compounds/naming-aromatic/v/naming-benzene-derivatives-introduction Go Now ^{}

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### Intermolecular forces (video) | Khan Academy

**Details: **In the video on electronegativity, we learned how to determine whether a covalent bond is polar or nonpolar. In this video, we're going to see how we figure out whether molecules are polar or nonpolar and also how to apply that polarity to what we call intermolecular forces.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/science/biology/chemistry--of-life/chemical-bonds-and-reactions/v/intermolecular-forces-and-molecular-bonds Go Now ^{}

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### Adding in binary (video) | Khan Academy

**Details: **Let's see what it's like to add multi-digit numbers in binary. So let's say I had the number one, zero, one, one. And to that I wanted to add the number one, one, one.

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› Url: https://www.khanacademy.org/math/algebra-home/alg-intro-to-algebra/algebra-alternate-number-bases/v/binary-addition Go Now ^{}

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### Preimage of a set (video) | Khan Academy

**Details: **Let's add some transformation that maps elements in set X to set Y. We know that we call X the domain of T. So that's my set X and then my set that I'm mapping into, set Y, that's the codomain.

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› Url: https://www.khanacademy.org/math/linear-algebra/matrix-transformations/linear-transformations/v/preimage-of-a-set Go Now ^{}

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### Intro to SQL: Querying and managing data | Khan Academy

**Details: **Learn how to use SQL to store, query, and manipulate data. SQL is a special-purpose programming language designed for managing data in a relational database, and is used by a huge number of apps and organizations.

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› Url: https://www.khanacademy.org/computing/computer-programming/sql/ Go Now ^{}

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### Vector examples (video) | Vectors | Khan Academy

**Details: **In the last video I was a little formal in defining what Rn is, and what a vector is, and what vector addition or scalar multiplication is. In this video I want to kind of go back to basics and just give you a lot of examples.

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› Url: https://www.khanacademy.org/math/linear-algebra/vectors-and-spaces/vectors/v/linear-algebra-vector-examples Go Now ^{}

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### IR spectra practice (video) | Spectroscopy | Khan Academy

**Details: **- [Voiceover] Let's look at some practice IR spectra, so here we have three molecules, a carboxylic acid, an alcohol, and an amine, and below there's an IR spectrum of one of these molecules.

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› Url: https://www.khanacademy.org/science/organic-chemistry/spectroscopy-jay/infrared-spectroscopy-theory/v/ir-spectra-practice Go Now ^{}

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### Addition and subtraction with significant figures (video

**Details: **We saw in the last video that when you multiply or you divide numbers, or (I guess I should say when you multiply or divide measurements) your result can only have as many significant digits as the thing with the smallest significant digits you ended up multiplying and dividing.

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› Url: https://www.khanacademy.org/math/arithmetic-home/arith-review-decimals/arithmetic-significant-figures-tutorial/v/addition-and-subtraction-with-significant-figures Go Now ^{}

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### How to motivate students who are distance learning during

**Details: **If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

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› Url: https://www.khanacademy.org/khan-for-educators/resources/parents-mentors-1/helping-your-child/a/how-to-motivate-students-who-are-distance-learning-during-covid Go Now ^{}

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### Area of a regular hexagon (video) | Khan Academy

**Details: **We're told that ABCDEF is a regular hexagon. And this regular part-- hexagon obviously tells us that we're dealing with six sides. And you could just count that.

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› Url: https://www.khanacademy.org/math/geometry/hs-geo-trig/hs-geo-special-right-triangles/v/area-of-a-regular-hexagon Go Now ^{}

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### Calculating conditional probability (video) | Khan Academy

**Details: **Voiceover:Rahul's two favorite foods are bagels and pizza. Let A represent the event that he eats a bagel for breakfast and let B represent the event that he eats pizza for lunch.

› Verified *3 days ago*

› Url: https://www.khanacademy.org/math/statistics-probability/probability-library/conditional-probability-independence/v/calculating-conditional-probability Go Now ^{}

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### Diels-Alder reaction (video) | Khan Academy

**Details: **- [Narrator] Diels–Alder reaction is a very important reaction because it's used a lot in synthesis to make complicated molecules. On the left we have our diene, so we have two double bonds in that molecule.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/science/organic-chemistry/conjugation-diels-alder-mo-theory/diels-alder-reaction/v/diels-alder-reaction-new Go Now ^{}

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### How to identify a Buddha (article) | Khan Academy

**Details: **If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

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› Url: https://www.khanacademy.org/humanities/art-asia/beginners-guide-asian-culture/buddhist-art-culture/a/how-to-identify-a-buddha Go Now ^{}

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### Common and systematic naming: iso-, sec-, and tert

**Details: **Let's see if we can get the molecular structure for butylcyclopentane. So you just break this up the way we've done it in the last several videos, the suffix is -ane, so it is an alkane, all single bonds.

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› Url: https://www.khanacademy.org/science/organic-chemistry/bond-line-structures-alkanes-cycloalkanes/naming-alkanes/v/common-and-systematic-naming-iso-sec-and-tert-prefixes Go Now ^{}

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### Subtracting in scientific notation (video) | Khan Academy

**Details: **- [Voiceover] What I want to do in this video is get a little bit of practice subtracting in scientific notation. So let's say that I have 4.1 x 10 to the -2 power. 4.1 x 10 to the -2 power and from that I want to subtract, I want to subtract 2.6, 2.6 x 10 to the -3 power.

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› Url: https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-numbers-operations/cc-8th-scientific-notation-compu/v/subtracting-in-scientific-notation Go Now ^{}

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### Domain and range of quadratic functions (video) | Khan Academy

**Details: **Determine the domain and range of the function f of x is equal to 3x squared plus 6x minus 2. So, the domain of the function is: what is a set of all of the valid inputs, or all of the valid x values for this function?

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› Url: https://www.khanacademy.org/math/algebra-home/alg-functions/alg-determining-the-range-of-a-function/v/domain-and-range-of-a-function-given-a-formula Go Now ^{}

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### Simplifying radical expressions (addition) | Algebra

**Details: **We're asked to add and simplify and we have the principle root of two x squared plus four times the principle root of eight plus three times the principle root two x squared plus the principle root of eight so we can do a little bit of adding, we can actually simplify first and then add or we can add first and then simplify but it looks like we can already add so lets try and do that so here

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› Url: https://www.khanacademy.org/math/algebra-home/alg-exp-and-log/miscellaneous-radicals/v/adding-and-simplifying-radicals Go Now ^{}

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### How to find domain and range from a graph (video) | Khan

**Details: **The function f of x is graphed. What is its domain? So the way it's graphed right over here, we could assume that this is the entire function definition for f of x.

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› Url: https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:functions/x2f8bb11595b61c86:introduction-to-the-domain-and-range-of-a-function/v/domain-and-range-from-graphs Go Now ^{}

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### Dimensions of a cube from its volume (video) | Khan Academy

**Details: **- [Voiceover] Let's say that we had a cube, let me draw the cube here, So we have a cube, and we know that the volume of this cube is equal to 512 cubic centimeters.

› Verified *6 days ago*

› Url: https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-numbers-operations/cc-8th-roots/v/dimensions-of-cube-from-volume Go Now ^{}

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### Linear equations 1 (video) | Khan Academy

**Details: **Welcome to level one linear equations. So let's start doing some problems. So let's say I had the equation 5-- a big fat 5, 5x equals 20. So at first this might look a little unfamiliar for you, but if I were to rephrase this, I think you'll realize this is a pretty easy problem.

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› Url: https://www.khanacademy.org/math/algebra-home/alg-basic-eq-ineq/alg-old-school-equations/v/algebra-linear-equations-1 Go Now ^{}

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### Introduction to electrical engineering | Khan Academy

**Details: **A summary of the math and science preparation that will help you have the best experience with electrical engineering taught on Khan Academy. Become familiar with engineering numbers and notation, and learn about the two most important electrical quantities: current and voltage.

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› Url: https://www.khanacademy.org/science/electrical-engineering/introduction-to-ee Go Now ^{}

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### Negative signs in fractions (video) | Khan Academy

**Details: **- We already know a good bit about negative numbers. And we know a good bit of fractions. So you can imagine we're going to start seeing negatives and fractions together a lot.

› Verified *3 days ago*

› Url: https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-negative-numbers-multiply-and-divide/cc-7th-mult-div-fractions-2/v/negative-signs-in-numerators-and-denominators Go Now ^{}

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### Program.restart() | ProcessingJS | Computer programming

**Details: **Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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› Url: https://www.khanacademy.org/computer-programming/programrestart-processingjs/5772421353439232 Go Now ^{}

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### Nonlinear equation graphs — Basic example (video) | Khan

**Details: **Watch Sal work through a basic Nonlinear equation graphs problem.

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› Url: https://www.khanacademy.org/test-prep/sat/sat-math-practice/new-sat-passport-advanced-mathematics/v/sat-math-p12-easier Go Now ^{}

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### Computer programming | Computing | Khan Academy

**Details: **Learn how to program drawings, animations, and games using JavaScript & ProcessingJS, or learn how to create webpages with HTML & CSS. You can share whatever you create, explore what others have created and learn from each other!

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› Url: https://www.khanacademy.org/computing/computer-programming Go Now ^{}

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### image(image, x, y, width*, height*) | ProcessingJS

**Details: **Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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› Url: https://www.khanacademy.org/computer-programming/imageimage-x-y-width-height-processingjs/937672662 Go Now ^{}

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### Mean absolute deviation (MAD) (video) | Khan Academy

**Details: **Mean absolute deviation (MAD) of a data set is the average distance between each data value and the mean. Mean absolute deviation is a way to describe variation in a data set. Mean absolute deviation helps us get a sense of how "spread out" the values in a data set are.

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› Url: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-data-statistics/cc-6-mad/v/mean-absolute-deviation Go Now ^{}

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### Determinant of a 3x3 matrix: standard method (1 of 2

**Details: **As a hint, I will take the determinant of another 3 by 3 matrix. But it's the exact same process for the 3 by 3 matrix that you're trying to find the determinant of.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/algebra-home/alg-matrices/alg-determinants-and-inverses-of-large-matrices/v/finding-the-determinant-of-a-3x3-matrix-method-2 Go Now ^{}

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### Condensed structures (video) | Khan Academy

**Details: **- Let's say we're given the molecular formula C three H eight O, and we're asked to draw a Lewis dot structure. So on the left here is one possible Lewis dot structure that you can draw that has that molecular formula.

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› Url: https://www.khanacademy.org/science/organic-chemistry/gen-chem-review/bond-line-structures/v/condensed-structures Go Now ^{}

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### The zeroth power (video) | Exponents | Khan Academy

**Details: **- If we think about something like two to the third power, we could view this as taking three twos and multiplying them together, so two times two times two, or equivalently, we could say this is the same thing as taking a one and then multiplying it by two three times, so actually, let's just go with this definition right over here, and this, of course, is going to be equal to eight.

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› Url: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-arithmetic-operations/cc-6th-exponents/v/the-zeroth-power Go Now ^{}

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### Analytic geometry | Geometry (all content) | Math | Khan

**Details: **In analytic geometry, also known as coordinate geometry, we think about geometric objects on the coordinate plane. For example, we can see that opposite sides of a parallelogram are parallel by writing a linear equation for each side and seeing that the slopes are the same.

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› Url: https://www.khanacademy.org/math/geometry-home/analytic-geometry-topic Go Now ^{}

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### Angle measurement & circle arcs (video) | Khan Academy

**Details: **We already know that an angle is formed when two rays share a common endpoint. So, for example, let's say that this is one ray right over here, and then this is one another ray right over here, and then they would form an angle.

› Verified *3 days ago*

› Url: https://www.khanacademy.org/math/basic-geo/basic-geo-angle/angles-in-circles/v/angle-measurement-and-circle-arcs Go Now ^{}

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### Perlin noise (article) | Noise | Khan Academy

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› Url: https://www.khanacademy.org/computing/computer-programming/programming-natural-simulations/programming-noise/a/perlin-noise Go Now ^{}

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### Null space 2: Calculating the null space of a matrix

**Details: **In the last video, I spoke somewhat theoretically about what a null space is and we showed that it is a valid subspace. But in this video let's actually calculate the null space for a matrix.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/math/linear-algebra/vectors-and-spaces/null-column-space/v/null-space-2-calculating-the-null-space-of-a-matrix Go Now ^{}

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### Measuring Line Segments (video) | Lines | Khan Academy

**Details: **In this example of measuring a line segment, the numbers span across the positive and negative. Remember, line segments and points are the foundations of geometry, so this is an important concept.

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› Url: https://www.khanacademy.org/math/geometry-home/geometry-lines/basic-geo-measuring-segments/v/measuring-segments Go Now ^{}

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### Balancing chemical equations (how to walkthrough) (video

**Details: **- Balancing chemical equations is one of those concepts in chemistry that often confuses people. But I think we'll see that if we work through this carefully and methodically, and we also appreciate the art of balancing chemical equations, that it's actually not too bad.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/science/ap-chemistry/stoichiometry-and-molecular-composition-ap/balancing-chemical-equations-ap/v/balancing-chemical-equations-introduction Go Now ^{}

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### Launching and landing on different elevations (video

**Details: **Let's do a slightly more complicated two-dimensional projectile motion problem now. So in this situation, I am going to launch the projectile off of a platform.

› Verified *2 days ago*

› Url: https://www.khanacademy.org/science/physics/two-dimensional-motion/two-dimensional-projectile-mot/v/launching-and-landing-on-different-elevations Go Now ^{}

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