Given that force 1=60 pounds and force 2=90 pounds, find the angle between the forces if the magnitude of the resultant force is 50 pounds. Round answer to the nearest degree and show work.

Answer 1

make a diagram,
obviously the angle between the two given forces must be obtuse.
Complete the parallogram

I see:
50^2 = 60^2 + 90^2 - 2(60)(90)cosØ
cosØ = 9200/10800 = .85185
Ø = 31.6°

so the angle between the two forces = 180-31.6= 148.4°
to the nearest degree ---- 148°