Question

I need help with this trig question part A and B

Answer 1

Part A: ∠A ≈ 27.7 °

Part B: c ≈ 8.75

Explanation:

Part A:

Use the Law of Cosines.

Cosθ =

[ a² + b² - c² ] / [ 2ab ]

Sub in all the information where θ is A.

A = cos⁻¹ { [10² + 7² - 5²] / [2×10×7]

A ≈ 27.7 ° (1 decimal place)

Part B:

Use the Law of Cosines, but instead the unknown is the side c.

Rearrange to isolate c:

c² = a² + b² - 2ab×cosθ

c = √(5² + 6² - 2×5×6×cos(105°))

c ≈ 8.75 (2 decimal places)