Question

There are two concertic circles . the radius of the outer circle is 10 cm and the radius of inner circle is 4 cm . find the area of the shaded portion . ( take ^ = 22/ 7)

Answer 1

Answer:

Let r1=10cm,r2=8cm

Area enclosed = Area of bigger circle – Area of smaller circle

=πr12–πr22

=π(100−64)=36π

Now

R1=r1+10010r1

R2=r2−10050r2

⟹R1=1.1r1,R2=2r2

Area enclosed =πR12–πR22

=π(1.21r12−4r22)

=π(121−16)=105π