Multiple choice

If the circumference of a circle is 132 cm then find the area of the semi-circle?

  1. 892 cm2

  2. 781 cm2

  3. 652 cm2

  4. 693 cm2

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Circumference = 2 * pi * r = 132. r = 132 / (2 * 22/7) = 132 * 7 / 44 = 21 cm. Area of semi-circle = (1/2) * pi * r^2 = 0.5 * (22/7) * 21 * 21 = 11 * 3 * 21 = 693 cm^2.

AI explanation

The full circumference is 132 cm, so using the circumference formula 2 times pi times radius, we have 132 = 2 times 22/7 times radius. This gives the radius as 21 cm. The area of the full circle is pi times radius squared, which is 22/7 times 441 = 1386 cm2; therefore, the area of the semi-circle is half of this, which is 693 cm2.

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