Jack walks x km on a bearing of 100 degrees from O, then y km on a bearing of 200 degrees to H. Calculate the magnitude and direction of the displacement vector OH when:

a) x=6, y=7

b) x=6, y=10

The answer to a) should be 8.4 KM, 155 degrees. And b) should be 10.7 km, 167 degrees, but I can't get these answers. Please help.