Given a= 108 degree, b=9 and c = 15, use the law of cosines to solve the triangle for the value of A. Round answer two decimal places. a. 19.13 b. 14.92 c. 19.73 d. 18.53

Question

asked Nov 1, 2020 10.5k views

1 Answer

Slonik · Answer 1 · 2020-11-05T14:41:47+0000

Answer:

c. 19.73

Explanation:

The Cosine rule shows states that:

a²=b²+c²-2bcCos A, where a, b and c are the sides of the triangle and A is the angle at vertex A.

A=108°

b=9

c=15

Substituting with the values above gives:

a²=9²+15²-(2×9×15 Cos 108)

a²=389.4346

a=19.73