Question

In ABC, BC = a = 16, AC = b = 10, and m = 22°. Which equation can you use to find the value of c = AB?

Answer 1

You can use the Law of Cosines to solve for c:

c2 = a2 + b2 − 2ab cos C = 162 + 102 − 2(10)(16) cos 22°.

Explanation:

PLATO

Answer 2

By cos Rule: c² = a² + b² -2abcosФ

c = 7.7

Explanation:

∵ AC = 10 , BC = 16 , m∠C = 22°

∴ We can use the cos Rule:

∵ c² = a² + b² -2abcos(C)

∴ c² = (10)² + (16)² - 2 × 10 × 16 cos(22)

∴ c² = 100 + 256 - 320cos(22) = 59.301167

∴ c = 7.7