posted by Reuben49 on .
Three towns p,Q and R are such that the distance between P and Q is 50km and the distance between p and R is 90km.if the bearing of Q from P is 075 and the bearing of R from p is 310, find the distance between Q and R correct to the nearest Km.
I made a sketch, drew some verticals at Q , P and R to get the bearings entered and found angle P = 125°
so use the cosine law:
QR^2 = 50^2 + 90^2 - 2(50)(90)cos125°
QR = 125.547... or 126 to the nearest km