Given ΔABC with m∠B = 98°, a = 26, and c = 14, what is the measure of A?

Question

Given ΔABC with m∠B = 98°, a = 26, and c = 14, what is the measure of A?

A.  m∠A = 26.4°

B. m∠A = 55.6°

C.  m∠A = 52.3°

D.  m∠A = 29.7°

Answer 1

By cosine law b = (26² + 14² - 2·26·14cos98°)^1/2 = 31.198

By sine law sinA/26 = sin98°/31.198; A = sin^-1(26sin98°/31.198) = 55.6°