CK-12 Foundation
Dilation in the Coordinate Plane: Lesson
Multiply coordinates to either shrink or enlarge a figure. An informative segment of a geometry playlist introduces dilation on the coordinate plane. The dilations in the resource use the origin as the center of dilation, which makes...
Khan Academy
Khan Academy: Geometry: Problem Involving Angle Derived From Square and Circle
Demonstrates how to solve a challenging geometry problem about finding the measure of an angle that is formed by different segments in a square which intersect with part of a circle. Solution depends on creating triangles in the diagram...
Khan Academy
Khan Academy: Geometry: Intro to 30 60 90 Triangles
Solves an example problem in which the length of the hypotenuse is known and the length of a side must be determined. Explains the special relationship of the lengths of the sides of a 30-60-90 triangle using the Pythagorean theorem....
Khan Academy
Khan Academy: Geometry: Median Centroid Right Triangle Example
This video tutorial [9:00]explains how to find various measures of triangles formed by the medians of a right triangle. Based on the properties of the medians of a triangle, properties of centroids, and the Pythagorean theorem.
Khan Academy
Khan Academy: Pythagorean Theorem Proof Using Similarity
This video tutorial lesson [9:52] provides a proof for the Pythagorean Theorem by breaking a right triangle into two similar triangles and setting up ratios of corresponding sides.
Khan Academy
Khan Academy: Trigonometry: 2003 Aime Ii Problem 11
Video demonstrates solving a trigonometric problem that includes finding the area of an oblique triangle using the Pythagorean Theorem and the law of cosines [16:35]
Khan Academy
Khan Academy: Geometry: Circumcenter of a Right Triangle
Proves that the circumcenter of a right triangle is the midpoint of the hypotenuse. [5:42]
Khan Academy
Khan Academy: Geometry: Ca Geometry: More Trig
The video tutorial [12:21] demonstrates solutions to problems #66-70 of California Geometry released state test questions. Problems address basic trigonometry ratios, 30-60-90 triangles.
Khan Academy
Khan Academy: Geometry: Similar Triangle Basics
Explains the difference between congruent triangles and similar triangles. Introduces the idea of scale factors. [9:17]
Khan Academy
Khan Academy: Trigonometry: Basic Trigonometry Ii
Continuation of video lesson introducing the basic trigonometric ratios. Examples of finding sine, cosine and tangent for two different right triangles, including finding side lengths by the Pythagorean Theorem and rationalizing the...
Khan Academy
Khan Academy: Basic Trigonometric Ratios: Using Trig Functions Part Ii
A couple of more examples of using Trig functions to solve the sides of a triangle. This video use the basic trigonometric functions to determine unknown side lengths of a right triangle. Example shows using trigonometry as well as the...
Khan Academy
Khan Academy: Dilating Shapes: Shrinking Down a Triangle by Half
Demonstrates how to plot a triangle on a Cartesian grid after a dilation and with a scale factor of 1/2. [2:26]
Khan Academy
Khan Academy: Trig Identities: Law of Cosines
Introduction to the law of cosines to solve for a side of a triangle when 2 sides and an angle are known.
Khan Academy
Khan Academy: Geometry: Angle Bisector Theorem Examples
Explains how to use the angle bisector theorem to solve for the sides of a triangle. [3:04]
Khan Academy
Khan Academy: Worked Examples: Geometry: Pythagorean Theorem, Area
Students watch a video tutorial to learn how to solve area problems of composite figures using the Pythagorean Theorem.
Khan Academy
Khan Academy: Trig to Solve the Sides and Angles of a Right Triangle
Worked example using trigonometry to solve for the lengths of the sides of a right triangle given one of the non-right angles.
Khan Academy
Khan Academy: Perpendicular Bisectors: Area Circumradius Formula Proof
Proof of the formula relating the area of a triangle to its circumradius.
Imagine Learning Classroom
Learn Zillion: Prove the Pythagorean Theorem: Using Similar Triangles
In this lesson, you will learn how to prove the Pythagorean Theorem by using similar triangles. [4:54]
Math Antics
Math Antics: The Pythagorean Theorem
Gain a basic understanding of the Pythagorean Theorem by watching this easy to understand video tutorial. Additional resources are available as part of a paid subscription service. [12:55]
PatrickJMT
Patrick Jmt: Law of Cosines, Example 1
Easy to follow video tutorial gives the formula for the Law of Cosines and uses it to find the missing side length of a triangle. [5:05]
Khan Academy
Khan Academy: Basic Trigonometric Ratios: Basic Trigonometry Ii
A few more examples using SOH CAH TOA. Examples of finding sine, cosine and tangent for two different right triangles, including finding side lengths by the Pythagorean Theorem and rationalizing the denominator.
Khan Academy
Khan Academy: More Trig Examples: 2003 Aime Ii Problem 11
Video demonstrates solving a trigonometric problem that includes finding the area of an oblique triangle using the Pythagorean Theorem and the law of cosines.
Khan Academy
Khan Academy: Triangles: Circumcenter of a Right Triangle
The video tutorial shows that the midpoint of the hypotenuse is the circumcenter.
Khan Academy
Khan Academy: Triangles: Pythagorean Theorem Proof Using Similarity
This video shows a proof for the Pythagorean Theorem by breaking a right triangle into two similar triangles and setting up ratios of corresponding sides.