1. The problem statement, all variables and given/known data At 9 a.m ship A is 50 km [E] of ship B. Ship a is sailing [N] at 40 km/h and ship B is sailing at 30 km/h. How fast is the distance between them changing at 12 am? 2. Relevant equations x^2 + y^2 = z^2 dz/dt [t=3h] = ? db/dt = 30 km/h da/dt = 40 km/h 3. The attempt at a solution My instructor made me draw out a diagram the diagram helped me determine that dy/dt = 70 km/h and that x = 50 km so: x^2 + y^2 = z^2 50^2 + y^2 = z^2 2y(dy/dt) = 2z (dz/dt) 2y(70) = 2z (dz/dt) Not sure if i'm doing this right/what to do next.