Question

Radius of two concentric circles are 4 cm and 3 cm respectively. Then area bounded by these circles will be:

(A) 22 cm²

(B) 12 cm²

(C) 32 cm²

(D) 18 cm²

Answer 1

Answer is (A) 22 cm²

Given : Radius of two concentre circle are 4 cm and 3 cm.

Thus, R= 4 cm, r = 3 cm

∴ Area between two concentric circles

= π(R² – r²)

= \(\frac { 22 }{ 7 }\) [(4)² – (3)²]

= \(\frac { 22 }{ 7 }\) × [(4 + 3) (4 – 3)]

= \(\frac { 22 }{ 7 }\) × 7 = 22 cm²