Trigonometric Ratios - Mathematics and Statistics for the Environment - page 103

A

5

3

B C

4

FIGURE 6.3 Illustration for Example 6.3.

■ EXAMPLE 6.2
Problem: Using Figure 6.2, find the measure of angle x to the nearest degree.

Solution:

Oppositeleg
Hypotenuse

12
15

sin x = = = 08 .

Use a scientific calculator to find the angle measure with a sine of 0.8.

Enter: 0.8 [2nd] or [INV]
Result: 53.13010235

So, the measure of angle x = 53°.

■ EXAMPLE 6.3
Problem: For the triangle shown in Figure 6.3, find sin C , cos C , and tan C .

Solution:

sin C = 2/5; cos C = 4/5; tan C = 3/4

REFERENCES AND RECOMMENDED READING
McKeague, M. and Charles, P. (1998). Algebra with Trigonometry for College Students . Saunders College
Publishing, Philadelphia, PA.
Smith, R.D. and Peterson, J.C. (2009). Mathematics for Machine Technology , 6th ed. Delmar, Clifton Park, NY.