Explanation:
The two forces form a right triangle.
The magnitude is found with Pythagorean theorem.
F² = Fx² + Fy²
F² = (-325 N)² + (452 N)²
F = 557 N
The direction is found with trigonometry:
θ = atan(Fy / Fx)
θ = atan(452 N / -325 N)
θ = -54.3° or 125.7°
θ is 125.7° from the +x axis (east). That corresponds to a direction of 35.7° west of north, or 54.3° north of west.
The net force has a magnitude of 557 N and a direction of 35.7° west of north.
