Question

The area enclosed between the circumferences
of two concentric circles is 346.5 cm2. The circumference of the inner circle is
88 cm. Calculate the radius of the outer Circle.

plz solve this quickly.​

Answer 1

Let radius of inner circle be r cm.

Circumference of inner circle = 88 cm.

2πr = 88

2 * (22/7) * r = 88

r = 14 cm

Area of inner circle = πr²

                                = 196π cm²

Now,

Let radius of outer circle be R cm.

Area of outer circle = πR² cm²

A.C.Q, we have

πR² - πr² = 346.5

π(R² - r²) = 346.5

R² = 306.25

R = 17.5

Therefore, radius of outer circle = 17.5 cm

Answer 2

Here's the answer

hope it helped