First resolved all the forces in horizontal and vertical direction, Clearly note that the angle measured by x-axis,
∑H = 4000 cos 45° + 3000 cos 90°+1000 cos 0°+5000 cos 225°
= 292.8N ...(i)
∑V = 4000 sin 45° + 3000 sin 90°+ 1000 sin 0°+5000 sin 225°
= 2292.8N ...(ii)
R2 = RH2 + RV2
R2 = (292.8)2 + (22923.8)2
R = 2311.5N
Let angle made by resultant is θ
tanθ = ∑V /∑H
= 2292.8/292.8
θ = 82.72º.