A circle is inside a square.

The radius of a circle is increasing at a rate of

5 meters per hour and the sides of the square

are increasing at a rate of 1 meter per hour.



When the radius is 4 meters,

and the sides are 18 meters

then how fast is the AREA between the circle and

the square changing?



The rate of change of the AREA enclosed between

the circle and the square is square meters per hour.

(Enter your answer as a decimal number rounded to 2 places.)