Khan Academy
Khan Academy: Triangles: Pythagorean Theorem Ii
More Pythagorean Theorem examples. Introduction to 45-45-90 triangles.
Imagine Learning Classroom
Learn Zillion: Find Tangent Value Using Side Ratios
In this lesson, you will learn how the ratios of certain sides of the triangle determine the tangent value of a particular angle by using properties of similar triangles. [2:13]
Study Pug
Study Pug: Pythagorean Theorem
In a nutshell, Pythagorean Theorem describes the relationship between the lengths and sides of a right triangle. Watch this video for a detailed explanation along with various examples. [8:48]
PatrickJMT
Patrick Jmt: Pythagorean Theorem
Video tutorial defines the Pythagorean theorem and features a few problems using it. [9:04]
Khan Academy
Khan Academy: Dilating Lines
Sal shows how we can use dilations to map a line into another, parallel, line.
Khan Academy
Khan Academy: Trig Word Problem: Stars
Sal solves a word problem about the distance between stars using the law of cosines.
Khan Academy
Khan Academy: Solving for a Side With the Law of Cosines
Learn how to use the law of cosines to find the missing side length of a triangle when given two side lengths and the contained angle measure.
Khan Academy
Khan Academy: Proof of the Law of Cosines
Sal gives a simple proof of the Law of cosines.
Sophia Learning
Sophia: Using Right Triangle Trigonometry to Find the Area of Regular Polygons
This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon.