Maggie is standing in her front yard and sees a balloon overhead traveling in and out of the clouds. The balloon is flying away from Maggie at a constant height and a constant speed of 15 feet/second.
When Maggie sees the balloon for the first time, she measures the angle between the balloon and the horizon to be 40 degrees. She sees the balloon again 10 seconds later, and measures the angle again: the angle is 30 degrees.
Find the height of the balloon.
Draw a diagram. If the height is h feet, then
h cot30° - h cot 40° = 15*10