Trigonometry For Dummies, 2nd Edition

Chapter 6

Getting It Right with Triangles

In This Chapter

Examining right triangles

Solving for lengths with Pythagoras's theorem

Defining special right triangles that make life easier

Triangles are classified in many ways. One way of distinguishing one triangle from another is to use angle measurements. Because a 90-degree angle is called a right angle, you use the same terminology to describe a triangle with a right angle in it. This type of triangle is called a right triangle. And that's all right.

The measures of the sides of right triangles are used to determine the values of the trig functions. And those trig functions (along with the right triangles) are really handy when it comes to solving problems such as “Just how high is that tree?” The special properties of a right triangle — some credited with Pythagoras — make them very useful in trigonometry and other math areas.

Sizing Up Right Triangles

If you're looking at their angles, triangles can be right, acute, or obtuse. Right triangles have been of great interest for centuries. They're the basis for applications in navigation, astronomy, surveying, and military engineering.

What's so right about them?

A right triangle ...