A triangle has side lengths of 9 in, 13 in, and 20 in. What is the measurement of this triangle’s largest angle? 29.9° 129.9° 136.2° 50.1°. Question A triangle has side lengths of 9 in, 13 in, and 20 in. What is the measurement of this triangle’s largest angle? 29.9° 129.9° 136.2° 50.1°. in progress 0 Math Eliza 4 days 2022-01-14T11:54:37+00:00 2022-01-14T11:54:37+00:00 1 Answer 0 views 0

## Answers ( )

Answer:x = 129.9degrees 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.