Assignment:
Only two forces act on an object (mass = 4.00 kg), as in the drawing. Find the magnitude and direction (relative to the x axis) of the acceleration of the object.

Ftotal=Sqrt(60^2+40^2)=72.11(N)
Angle=tan-1(60/40)= 56.3° (How did you get 56.3°)
a= F/m=72.11/4=18(m/s/s)