Hello, I need a little help with a few differentiation problems with angles:

1. A balloon rises at a rate of 3 meters per second from a point on the ground 30 meters from an observer. Find the rate of change of the angle of elevation of the balloon from the observer when the balloon is 30 meters above the ground.

and

2. A fish is reeled in at a rate of 1 foot per second from a point 10 feet above the water. At what rate is the angle between the line and the water changing when there is a total of 25 feet of line out.

I just need help on getting started: equations to use, etc. I have no idea what I am doing wrong.

Thanks