*Macmillan Science Library: Mathematics*. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.

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## Trigonometric Ratios

To understand the six trigonometric functions, consider right triangle *ABC* with right angle *C.* Although triangles with identical angle measures may have sides of different lengths, they are similar. Thus, the ratios of the corresponding sides are equal. Because there are three sides, there are six possible ratios.

Working from angle *A,* label the sides as follows: side *c* represents the **hypotenuse**; leg *a* represents the side opposite angle *A*; and leg *b* is adjacent to angle *A.* The definitions of the six trigonometric functions of angle *A* are listed below.

For any angle **congruent** to angle *A,* the numerical value of any of these ratios will be equal to the value of that ratio for angle *A.* Consequently, for any given angle, these ratios have specific values that are listed in tables or can be found on calculators.

**Basic Uses of Trigonometry.** The definitions of the...

This section contains 1,618 words(approx. 6 pages at 300 words per page) |