Use the cosine function to find the indicated part of triangle ABC. Round to four significant digits. Find c if A = 25° and b = 21 ft.
A)19.03 ft
B)23.17 ft
C)0.04316 ft
D)49.69 ft

Question

Use the cosine function to find the indicated part of triangle ABC. Round to four significant digits. Find c if A = 25° and b = 21 ft. 
A)19.03 ft 
B)23.17 ft 
C)0.04316 ft 
D)49.69 ft

Quizplus · Accepted Answer

Using the cosine function:

cos A = adjacent/hypotenuse

cos 25° = 21/c

c = 21/cos 25°

c ≈ 23.17 ft (rounded to four significant digits)

Use the Cosine Function to Find the Indicated Part of Triangle