Question

Find the area of circular track whose outer and inner radius is 5cm and 4cm. the option are :
A:41πcm B:16πcm C:25πcm D:9πcm.

Answer 1

to get the area of circular track we have to subtract the inner area from outerwear
$\pi( {5}^{2} - {4}^{2} )$
$\pi(5 - 4)(5 + 4)$
$\pi(9)$
there fore the answer is
$9\pi$