Figure below act on an object.

What fourth must act on the object so that the object does not accelerate?
T54D_
-3
4 Fx (N)
7.02 N + 2.0j N
3.02 N + 4.0j N
3.07 N - 4.0j N
-1.07 N + 5.0j N
1.02 N - 5.0j N

3.07 N - 4.0j N

In order for the object to not accelerate, the net force acting on the object must be zero. Therefore, the fourth force that must act on the object is equal in magnitude but opposite in direction to the sum of the other three forces. The sum of the given forces is 7.02 N + 2.0j N + 3.02 N + 4.0j N = 10.04 N + 6.0j N. Therefore, the fourth force should be -10.04 N - 6.0j N, which is equivalent to 3.07 N - 4.0j N in component form.