Respuesta :
Answer:
x = 129.9 degrees to the nearest tenth.
Step-by-step explanation:
The largest angle will be opposite the longest side (20 in). So by the Cosine Rule:
20^2 = 9^2 + 13^2 - 2*9*13 cos x where x is the largest angle.
cos x = (20^2-0.640 - 9^2 - 13^2) / (-2*9*13)
cos x = -0.641025641
x = 129.87 degrees.
