Please help with a related rates problem! Will fan and medal!

Question

anonymous · Answer

A rotating beacon is located 2 miles out in the water. Let A be the point on the shore that is
closest to the beacon. As the beacon rotates at 10 revolutions per minute, the beam sweeps
down the shore once each time it revolves. Assume that the shore is straight. How fast is the
point where the beam hits the shore moving at an instant when the beam is lighting up a point
2 miles downshore from point A?

anonymous · Answer

So far, I know that there is a triangle with angle theta at the beacon/lighthouse and that, because of the circle of its revolutions, dtheta/dt= 20pi

anonymous · Answer

Also, because it is asking for the instantaneous speed at x=2miles (for side x on this triangle) I am solving for dx/dt

jim_thompson5910 · Answer

Do you have a drawing set up?

anonymous · Answer

@jim_thompson5910 Thank you very much, but I just got it all figured out!

jim_thompson5910 · Answer

ok great, I'm glad you did