hey, ive recently discovered that related rates is my weakest topic in calculus:confused:. i was hoping i could get some help with a few problems.

1) A ladder 25 feet long leans against a vertical building. If the bottom of the ladder slides away from the building horizontally at a rate of 15 ft/sec, at what rate is the angle between the ladder and the ground changing when the top of the ladder is 7 feet above the ground?

and

2) A missile is fired vertically from a point that is 5 miles from a tracking station and at the same elevation as the tracking station. For the first 20 seconds of flight, the missile's angle of elevation (theta) changes at a constant rate of 2 degrees per second. Find the velocity of the missile when the angle of elevation is 30 degrees.

Any and all help is greatly appreciated. Thanks in advance.