Respuesta :
The angles can solved by using the cosine law. Solving for the measure of angle A
15² = 20² + 12² - 2(20)(12) cos A
A = 48.35°
Angle B can solved by either also using the cosine law or by sine law. Let's use sine law:
20 / sin B = 15 / sin 48.35
B = 85.06°
The measure of angle C can just be solved by difference of the total angle of the triangle.
C = 180 - 48.35 - 85.06
C = 45.59°
15² = 20² + 12² - 2(20)(12) cos A
A = 48.35°
Angle B can solved by either also using the cosine law or by sine law. Let's use sine law:
20 / sin B = 15 / sin 48.35
B = 85.06°
The measure of angle C can just be solved by difference of the total angle of the triangle.
C = 180 - 48.35 - 85.06
C = 45.59°