Answer:
6.7 m/s @ 116.6°
Explanation:
Use Pythagorean theorem to find the magnitude:
v² = vx² + vy²
v² = (-3 m/s)² + (6 m/s)²
v = √45 m/s
v ≈ 6.7 m/s
Use trigonometry to find the direction:
θ = atan(vy / vx)
θ = atan(6 m/s / -3 m/s)
θ = atan(-2)
θ ≈ 116.6° from the +x axis, or 63.4° north of west.
