Question

CAN SOMEONE HELP ME

Triangle not drawn to scale
Given: measure of angle A = 15 degrees, b = 16, and
c = 18. What is the length of a to the nearest tenth?

Answer 1

a ≈ 4.9

Explanation:

using the Cosine Rule in Δ ABC

a² = b² + c² - (2bc cosA )

= 16² + 18² - (2 × 16 × 18 × cos15° )

= 256 + 324 - (576cos15° )

= 580 - 576cos15

= 23.6267 ( take square root of both sides )

a =
`√(23.6267)`

≈ 4.9 ( to the nearest tenth )