Answer:
R ,is the Resultant of two forces, [tex]F_{1},F_{2}[/tex]
∠ACB +50°=180°
∠ACB=180° -50°
∠ACB=130°
[tex]R^{2} =[F_{1}]^2+[F_{2}]^2-2\times F_{1}\times F_{2} \times \cos(\angle ACB )\\\\R^2=(40)^2 +(38)^2-2 \times 40 \times 38 \cos(\angle 130 ^{\circ})\\\\R^2=1600+1444-3040\times (-0.6427)\\\\ R^2=3044+1953.808\\\\ R^2=4997.808\\\\R=70.695[/tex]
→Cos(130°)=Cos (180°-50°)= -cos 50°= -0.6427
Magnitude of resultant force =70.70 Newtons(Approx)
