Khan Academy
X and Y Intercepts 2
Given a linear equation in standard form, find the x-intercept and y-intercept. In this video, Sal shows how one can set x = 0 and solve the y-intercept, and how you can set y = 0 and find the x-intercepts.
Curated OER
Unemployment Rate Primer
Ever wonder how the Bureau of Labor Statistics calculates the ever-changing unemployment rate? Sal begins explaining this by breaking down the US population into subsets, including the labor force and the unemployed. He explains the...
Khan Academy
Two Passing Bicycles Word Problems
In this video, Sal solves a word problem sent in by a listener that has two cyclists riding towards each other over a given amount of time. It is an interesting problem regarding ratios and the relationship between distance, rate, and...
Khan Academy
Trigonometry Word Problems (Part 1)
Sal starts to solve a trigonometric word problem of a wayward ship captain who veers off course and once aware of his predicament, needs to know how far he is from his destination. Instead of using the Law of Cosines in his solution, Sal...
Curated OER
Trigonometric System Example
Sal solves a challenging problem that consists of a system of three trigonometric equations and three unknowns.
Curated OER
Trig Identities Part 2 (Part 4 if you watch the proofs)
In this video, Sal reviews the basic trigonometric definitions and identities including the sum of angles formulas and then derives the double angle formulas.
Curated OER
Triangle Medians and Centroids
The terminology used in geometry, including such words as centroid and median are discussed in this video. Through this lecture, young mathematicians can see a visual representation both median and centroid. Also, a proof showing how to...
Khan Academy
Triangle Medians and Centroids (2D Proof)
After addressing the terminology used with medians and centroids of triangles in the first part of this series, the instructor shows how to solve this type of problem. He illustrates the concepts by using a high-level problem....
Khan Academy
The Mohorovicic Seismic Discontinuity
The phenomena observed in the behavior of waves and data received from seismographs can lead us to various conclusions about the densities of material that waves are passing through.
Curated OER
The Angle Game
A motivating activity is coupled with the use of algebra to explore the process for identifying the value of an angle. Somehow, it feels like a bit like magic when Sal shows the solution for the final problem. Also, it would be...
Curated OER
Testing if a Relationship is a Function
This short video looks at different points on a coordinate plane and answers a question about whether these points could represent a function. The answer is determined by looking at each point individually to determine whether given a...
Curated OER
Taking Percentages
There are two percentage concepts covered in an informative video. The first is how to find a given percent of a given number; the second concept shows learners how to find a number when the percent is given. Sal finishes by...
Khan Academy
Sum of Consecutive Odd Integers
The sum of three consecutive odd integers is 231. What is the largest integer? See how to unpack this word problem, set up an equation, and solve for the variable.
Khan Academy
Solving for a Variable 2
The instructor uses the formula for temperature to show how the variables can be moved around to solve a problem.
Khan Academy
Solving Equations with the Distributive Property
Here is an equation in which the first step is to use the distributive property to get rid of the parenthesis. Then it is solved for the variables. Since there are variables on both sides of the equation, it is important to verify the...
Khan Academy
Solving Equations 2
Sal offers an example showing how to manipulate numbers on either side of the equal sign to isolate the variable and solve the equation.
Khan Academy
Solving Equations 1
Sal demonstrates how to solve an equation. He begins by saying that the variable needs to be isolated. He shows how to move numbers on either side of the equal sign to isolate the variable. He also shows how to verify answers by plugging...
Khan Academy
Solving a Quadratic by Factoring
Solving quadratics by factoring is the main concept in this video. Several examples are shown with positive numbers and with negative numbers. The instructor demonstrates how to set the factored equation to zero to solve the quadratic....
Curated OER
Slope and Y-Intercept Intuition
The instructor uses a computer graphing program to illustrate how a line changes slope by manipulating the slope values in the equation. He also manipulates the y-intercept value to see where the line crosses the y-axis.
Curated OER
Slope and Rate of Change
Introducing slope as "a way of measuring the inclination of a line," Sal endeavors to provide a working knowledge of slope problems and problem solving. The video is framed as a review, but could be a good way to fill any holes in...
Khan Academy
Simple Equations
Basic algebraic equations of the form Ax=B are dissected. Sal encourages viewers to fully understand what the equations represent prior to learning how to manipulate them. Furthermore, he teaches students how to solve the equations...
Khan Academy
Similar Triangles (Part 2)
Building on concepts in the first part of the series on similar triangles, installment number two explores how to find the values for given angles in a triangle. These problems are solved by using algebra and ratios. A step-by-step...
Khan Academy
Scientific Notation Examples
The problems in this video contain additional examples of scientific notation, continued from the previous presentation. Viewers have the opportunity to see Sal work through several more problems using the same techniques he has been...
Khan Academy
Rhombus Diagonals
Delving into a proof that the diagonals of a rhombus are perpendicular to each other, this lecture evaluates the angles and sides of this figure. It would serve as a great test preparation activity.