P,Q,R are three ships at sea. The bearing of Q from P is 030° and the bearing of P from R is 300°. If the distance between P and Q is 7km and that of P and R is 9km. Calculate correct to 3 significant figures the distance between.

Question

P,Q,R are three ships at sea. The bearing of Q from P is 030° and the bearing of P from R is 300°. If the distance between P and Q is 7km and that of P and R is 9km. Calculate correct to 3 significant figures the distance between.
a. Q and R
b. Bearing of Q from R

mathhelper · Answer

My diagram shows angle P - 90°, so
RQ^2 = 81+49
RQ = √130 = .....

For the angle at R:
tanR = 7/9
angle R = appr 37.9°
But PR was 60° from the vertical
so angle R = 22.1°

which means the bearing of Q from R is 337.9°

check my calculations