Round your answers to the nearest tenth for degrees and to the nearest hundredth for sides.

Question

q = 80

r = 60

s = 100



Q = ?  Degrees

Answer 1

Since you have three side lengths given and you want to solve for an angle, use the Law of Cosines:

 

q^2 = r^2 + s^2 - 2(rs)cos(Q)

 

You'll have those values of q, r, s substituted in, and then you'll solve for Q by rearrangement and taking an inverse cosine of the result.