Question

If the area of the circular pathway is 352 sq. cm and the outer radius is 16 cm, find the inner radius.

Answer 1

Given outer radius R = 16 cm

Area of the circular pathway = πR² = πr²

Area of the circular pathway = 352 sq. cm

πR² – πr² = 352 cm²

π(R² – r²) = 352

16² – r² = \(\frac{352\times7}{22}\)

16² – r² = 16 x 7

16² – r² = 112

16² – 112 = r²

r² = (256 – 112) cm²

r² = 144 cm²

r = 12 cm

Inner radius r = 12 cm