Question:

(a) A kite string is being paid out at a rate of 3 ft/sec. If the wind carries the kite horizontally at an altitude of 200 ft, how fast is the kite moving when 400 ft of the string have been paid out?

(b) Each vertical end of a 20-ft long water trough is an equilateral triangle with the vertex down. If water is being pumped in at a constant rate of 4ft³/min, how fast is the level of the water rising when the water is 1 ft deep