Looks like a situation for the law of cosines.
b^2 = a^2 + c^2 - 2ac cos B
17.64 = 60.84 + 15.21 - 60.84 cos B
cos B = 0.9601
B = 16.2 degrees
In triangle ABC, a=7.8, b=4.2, c=3.9. Find B
a. 15.1°
b. 148.7°
c. 78.9°
d. 16.2 °
It is D, right?
1 answer