Multiple choice

Find the area of a circular ring formed by two concentric circles whose radii are $5.7\ cm$ and $4.3\ cm$ respectively (Take $\pi =3.1416$)

  1. $43.98$ sq. cm
  2. $53.67$ sq. cm
  3. $47.24$ sq. cm
  4. $38.54$ sq. cm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Area = pi * (R^2 - r^2) = 3.1416 * (5.7^2 - 4.3^2) = 3.1416 * (32.49 - 18.49) = 3.1416 * 14 = 43.9824.

AI explanation

The area of a circular ring is found by subtracting the area of the inner circle from the area of the outer circle using the formula pi multiplied by the difference of the squares of the radii. Calculating the difference of the squares of 5.7 and 4.3 gives 32.49 minus 18.49, which is 14. Multiplying this difference by 3.1416 gives an area of 43.98 square centimeters.

Keep practicing — related questions