Question

Which of the following applies the law of cosines correctly and could be solved to find m∠Q? ANSWERS: A) 302 = 182 + 172 – 2(18)(17) ⋅ cos Q B) 182 = 302 + 172 – 2(30)(17) ⋅ cos Q C) 302 = 182 + 172 – cos Q D) 182 = 302 + 172 – cos Q

Answer 1

Explanation:

Law of cosines: c^2 = a^2 + b^2 − 2ab cos(C)

Used to find: the angles of a triangle when we know all three sides

We are looking for: Angle Q. The side opposite Angle Q (30) can be c. Line segments RQ and QS are a(17) and b(18).

30^2 = 18^2 + 17^2 - 2(17)(18) cos (q)