Special Right Triangles Topic Index | Algebra2/Trig Index | Regents Exam Prep Center

There are two "special" right triangles with which you need to be familiar;  the 45º- 45º- 90º triangle and the 30º- 60º- 90º triangle.  The "special" nature of these triangles is their ability to yield exact answers instead of decimal approximations when dealing with trigonometric functions.

These triangles will be used continually throughout your studies of mathematics and are well worth your time and study.

 The most powerful method of working with these triangles is to work directly with the triangles themselves.  By remembering the "relationships" in these triangles, you will have the power to apply any of the six trigonometric functions in any situation.

Some people find charts helpful for remembering the trigonometric values of 30º, 45º, and 60º.  Unfortunately, memorizing charts of information often gives you a limited understanding of the concepts at hand.  For example, if a chart is limited to only a few of the trigonometric functions, such as the charts seen below, your "power" to solve a multitude of problems is also limited.

 30º 45º 60º sin cos

This chart shows the values with
rationalized denominators.

 30º 45º 60º sin cos

This chart shows a "trick" for remembering the values.  Notice the row for sin shows 1, 2, 3 under the radicals, while the row for cos shows 3, 2, 1 under the radicals.

 Let's move on to studying the triangles themselves.

 Topic Index | Algebra2/Trig Index | Regents Exam Prep Center Created by Donna Roberts