a body is at equilibrium under the action of three forces.one force is 10N acting due east and one is 5N in the direction 60¡ã northeast . what is the magnitude and direction of the third force

Answer 1

Northeast is E45°N or N45°E.
Assuming you mean E60°N, that means

<10,0> + <5/2,5√3/2> + <x,y> = <0,0>