Multiple choice

The circumference of a circle is $31.4\ cm$ Find the radius and the area of the circle? (Take $\pi=3.14$)

  1. $58.5cm^2$
  2. $48.5cm^2$
  3. $78.5cm^2$
  4. $88.5cm^2$
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C Correct answer
Explanation

Circumference = 2 * pi * r = 31.4. 2 * 3.14 * r = 31.4. r = 31.4 / 6.28 = 5. Area = pi * r^2 = 3.14 * 25 = 78.5.

AI explanation

Using the circumference formula, we set 31.4 equal to 2 multiplied by pi and the radius. Dividing 31.4 by 6.28 gives the radius as 5 centimeters. Then, using the area of a circle formula, we multiply pi by the radius squared to get 3.14 multiplied by 5 squared, which equals 3.14 multiplied by 25, resulting in an area of 78.5 square centimeters.

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