two forces of 600 N and 186 N act at a point the resulatant

two forces of 600 N and 186 N act at a point. the resulatant force is 668 N. find the angle between the two forces

Solution

using cosine law which is

c²=a²+b²-2ab cos theta

668²=600²+ 186²-2(600)(186)cos theta

223200 cos theta= -51628

cos theta= -51628/223200=103.4 degree