Question

9
find the area of ring
circles whose circumference
between two concentric
are 75cm and 55cm.​

Answer 1

Answer:

I)2 πr=75,r=75 / 2π

2)2 πr=55, r = 55/2π

1) area= πr^2 = π(75 /2π)^2 =5625 / 4π.

=5625 x 7/ 4x22 = 447.4cm2

2) area= πr^2 = π(55/2π) ^2

= 3025x7/4x22=240,6cm2

Area of ring circles =447.4-240, 6

= 206.8cm2