The area of a circle is given by

c

i

r

c

l

e

$\_$

a

r

e

a

$=$

$\backslash$pi

$$

c

i

r

c

l

e

$\_$

r

a

d

i

u

s

$2$

$.$ Read circle$\_$radius from input as a float and compute circle$\_$area using the formula.