Answer:
AB = 15 A = 36.9 B = 53.1
Explanation:
A2 + B2 = C2
12(2 + 9(2 = 144 + 81 or 225 = C2
sqaure 225 to get rid of the exponent
so C = 15 or AB = 15
Divide your Oppisite by Hypo so 9/15 = .6
then use x = sin-1(0.6) to find angle A or 36.9
then add 36.9 to 90 and minus that from 180
so 180 - 126.9 = 53.1