What are the magnitude v and angle of the change in velocity if the initial velocity

What are the magnitude Δv and angle θ of the change in velocity if the initial velocity is 70.0 m/s south and the final velocity is 60.0 m/s west? Let the angle θ be measured relative to the east direction (e.g., θ=90^∘ means δv points north, θ=180^∘ means δv points west, etc.).

Δv = ? m/srn
θ= ?