if two forces acting on a body at angle ¤ to each other and exerts a force of 20N,their resultant is 30N.what is the angle between them?

each force is 20?

then
20 cos (T/2) + 20 (cos T/2) = 30

cos (T/2) = .75

T/2 = 41.4

T = 82.8 degrees