A ring-shaped metallic sheet has outer and inner radii 14 cm and 7 cm. What percentage of the full circle's area is the ring?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 75%.
Outer radius (R) = 14 cm
Inner radius (r) = 7 cm
Area of the full circle = πR2 = π × 142 = 196π
Area of the inner circle = πr2 = π × 72 = 49π
Area of the ring = 196π − 49π = 147π
Percentage of the full circle's area occupied by the ring = (147π/196π) × 100 = 75%