Hello, mistykz!

A girl flies a kite at a height of 300 ft,

the wind carrying the kite horizontally away from her at a rate of 25 ft/sec.

How fast must she let out the string when the kite is 500 ft away from her? I wouldn't introduce trigonometry . . .

Code:

B x C
* - - - - - - - - * →
| *
| *
300 | * S
| *
| *
A * - - - - - - - - - - - - -

The girl is at

The kite is at height of 300 feet:

. . and is moving from point at the rate of ft/sec.

The string has length:

Pythagorus says: . .**[1]**

Differentiate with respect to time: .

. . Hence, we have: . .**[2]**

When , [1] becomes: .

Substitute into [2]: . ft/sec