Practice similar

Attempt $5$: $1$ attempt remaining.

The radius of a circular puddle is growing at a rate of $11c\frac{m}{sec}.$

a$.$ How fast is its area growing at the instant when the radius is $31$ cm $?($Round your answer to the nearest whole number.$)$

$$

$c\frac{m^2}{sec}$

b$.$ How fast is the area growing when the area is $81$ square centimeters? $($Round your answer to the nearest whole number.$)$

$c\frac{m^2}{sec}$