Multiple choice

The circumference of a circle is 123.2 cm. Taking $\pi \, =\, \displaystyle \frac{22}{7}$, calculate the area of the circle in $cm^2$, correct to the nearest $cm^2$ is

  1. $196\, cm^2$
  2. $1207\, cm^2$
  3. $2414\, cm^2$
  4. $2207\, cm^2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Circumference = 2 * pi * r = 123.2. r = 123.2 / (2 * 22/7) = 123.2 * 7 / 44 = 19.6. Area = pi * r^2 = (22/7) * 19.6 * 19.6 = 22 * 2.8 * 19.6 = 1207.36. Rounded to the nearest integer, it is 1207.

AI explanation

The radius equals the circumference divided by 2 pi, so 123.2 divided by 44 divided by 7 gives 19.6 cm. The area is pi times the square of the radius, so 22 divided by 7 times 19.6 times 19.6 equals 1207.04 square cm. Rounding to the nearest whole number gives 1207 square cm.

Keep practicing — related questions