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, 1. The Distance between q and r 2. Bearing of r from p
PQ is 90 - 75 = 15 deg above x axis
PR is 310 - 270 = 40 deg above -x axis
so angle RPQ = 180 - 15 - 40 = 125
QR^2 = PR^2 + PQ^2 -2 PQ PR cos 125
= 90^2 + 50^2 - 2 * 90*50 *( -0.574)
then use law of sines to find the other angles