Khan Academy
Khan Academy: Geometry: 30 60 90 Triangle Example Problem
In this video tutorial [6:40], the instructor explains how to apply the relationships of the sides of a 30-60-90 triangle to solve a perimeter problem involving a rectangle that has had one of the angles trisected.
Khan Academy
Khan Academy: Algebra: Complex Numbers: Complex Roots From the Quadratic Formula
Video shows how to use the quadratic formula to find roots of a quadratic equation in a situation where the roots are complex. Includes showing how to verify the answers are correct solutions of the quadratic. [10:15]
Khan Academy
Khan Academy: Algebra: Solving One Step Equations 2
This video demonstrates how to solve a one-step equation using division and multiplication. It also shows how to check the answer by plugging it back into the equation. [2:23]
Khan Academy
Khan Academy: Algebra: Inequalities on a Number Line
A step-by-step video demonstrating how to graph inequalities on a number line. Practice problems available. [1:34]
Khan Academy
Khan Academy: Statistics: Chi Square Distribution Introduction
Video gives an introduction to what the chi-square distribution represents. Explains the effect of the degrees of freedom on the distribution and shows a graphical representation of the distribution with different degrees of freedom....
Khan Academy
Khan Academy: Pre Calculus: Compound Interest and E (Part 2)
Continuing from a previous video, this segment illustrates that as interest is compounded at increasingly more intervals, the debt owed approaches the number e (if $1 is borrowed at a rate of 100%). The instructor provides the ground...
Khan Academy
Khan Academy: Pre Calculus: Complex Determinant Example
A video showing the step-by-step solution to a difficult determinant problem from the IIT-JEE. This is problem 53 from Paper 1 of the 2010 exam. A 3 X 3 matrix is given in terms of z and omega, where omega is defined as a complex number...
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Khan Academy: Trigonometry: 2003 Aime Ii Problem 14
Video demonstrates solving a trigonometric problem that includes finding the area of a convex equilateral hexagon in the coordinate plane using trigonometric identities and the Pythagorean Theorem. [18:18]
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Khan Academy: Algebra: Approximating Square Roots
Video showing how to approximate the square root of a number to the hundredths place without using a calculator. [7:12]
Khan Academy
Khan Academy: Algebra: Polynomials 1
Video demonstrates how to write a polynomial that represents the difference between the area of a rectangle of given length and width and the area of a circle with a given diameter. [4:37]
Khan Academy
Khan Academy: Algebra: Midpoint Formula
This video demonstrates how to find the coordinate of the midpoint between two points on a coordinate plane by taking the mean of the x values and the mean of the y values. Practice problems available. This video is also found in the...
Khan Academy
Khan Academy: Algebra: Solving Systems by Graphing 3
This video demonstrates how to graph a system of equations and identify how many solutions it has. [5:08]
Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Adding Decimals of Different Signs
This video shows how to add positive and negative money amounts in the context of a word problem using a number line. Practice problems are available. [3:15]
Khan Academy
Khan Academy: Algebra: Multiplication of Polynomials
Video demonstrates several different types of polynomial multiplication problems: monomial by binomial, monomial by trinomial, binomial by binomial, binomial by polynomial. This video also appears in the Algebra: ck12.org strand....
Khan Academy
Khan Academy: Geometry: Ca Geometry: Circle Area Chords Tangent
Demonstrates solutions to problems #71-75 of California Geometry released state test questions. Problems address Pythagorean theorem, 45-45-90 triangles, 30-60-90 triangles, circumscribed polygons, area, chord length, tangents to circles...
Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Repeating Decimals to Fractions 1
This video explains how to convert a repeating decimal to a fraction. Practice problems are available. [4:03]
Khan Academy
Khan Academy: Geometry: Ca Geometry: More on Congruent and Similar Triangles
Demonstrates solutions to problems #17-20 of California Geometry released state test questions. Problems address understanding of similar triangles, parallelograms and properties of the diagonals of parallelograms. [11:11]
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Khan Academy: Algebra: Polynomial Division
Video demonstrates polynomial long division using four different example problems. This video also appears in the Algebra: ck12.org strand. [12:09]
Khan Academy
Khan Academy: Statistics: Sampling Distribution of the Sample Mean
Video reviews the central limit theorem and uses a simulation to illustrate sampling distributions and how they approach a normal distribution with larger sample sizes even if the original distribution was not normal. Also discusses the...
Khan Academy
Khan Academy: Algebra: Inequalities
Video demonstrating how to solve a real-world inequality problem. [2:09]
Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Number as Decimal, Percent, Fraction
This video explains how to represent a percent as a decimal and as a fraction. Practice problems are available. [3:32]
Khan Academy
Khan Academy: Algebra Ii: Quadratics and Shifts
Demonstrates solutions to four problems. Problems address understanding of quadratic equations, ways to solve quadratic equations, and translations of graphs of quadratic equations. Practice problems available. [11:53]
Khan Academy
Khan Academy: Geometry: Triangle Medians and Centroids
This video tutorial [8:59] reviews the definitions of median and centroid in relation to a triangle and proves that the centroid is two-thirds the way along a median. The proof is done be drawing a triangle in three-dimensions.
Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Order of Operations
This video demonstrates the order of operations in a numerical expression. Practice problems are available. [9:40]