calc 1 related rates

Question

A hot air balloon rising vertically is tracked by an observer located 5 miles from the lift-off point. At a certain moment, the angle between the observer's line-of-sight and the horizontal is  , and it is changing at a rate of 0.1 rad/min. How fast is the balloon rising at this moment?

Answer 1

The height of the balloon is 5 tan θ.

(dh/dt) = 5 sec²θ (dθ/dt)

Plug in the values give.