physics
posted by ba .
A person looking out the window of a stationary train notices that raindrops are falling vertically down at a speed of 4.15 m/s relative to the ground. When the train moves at a constant velocity, the raindrops make an angle of 25° when they move past the window, as the drawing shows. How fast is the train moving?

V/4.15 = tan 25
Do you see why? Think about it.
Solve for V