## Engineering Mechanics: Statics & Dynamics (14th Edition)

$\theta = 36.3°$ $\phi = 26.4°$
We are given the modules of F1, F2, F and the direction of the last. We are asked the angles of the other forces within the x axis. Applying the law of cosines, we know that $40^{2} = 30^{2} + 60^{2} - 2 \times 30 \times 60 \times \cos (\theta)$ $\theta = 36.34° \approx 36.3°$ And also $30^{2} = 40^{2} + 60^{2} - 2 \times 40 \times 60 \times \cos (\phi)$ $\phi = 26.38° = 26.4°$