Answer:
A = 31.68°
B = 109.45°
C = 38.92°
Step-by-step explanation:
Law of cosine: cosA = (b²+c²-a²) / 2bc
a = x = 10 b = 18 c = 12
cosA = (18² + 12² - 10²) / 2*18*12 = 368/432 = 0.851
A = 31.68
cosB = (10² + 12² - 18²) / 2*10*12 = -80/240 = -1/3 = -0.333
B = 109.45
cosC = (10² + 18² - 12²) / 2*10*18 = 280/360 = 0.778
C = 38.92
check: A+B+C = 31.68 + 109.45 + 38.92 =180.05 ≈ 80°
Wish this help!!
