Multiple choice

If area of a semi-circle is 308 cm2, then find its radius (in cm).

  1. 28

  2. 10

  3. 20

  4. 14
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Area of a semi-circle = (1/2) * pi * r^2 = 308. (1/2) * (22/7) * r^2 = 308. (11/7) * r^2 = 308. r^2 = 308 * 7 / 11 = 28 * 7 = 196. r = 14.

AI explanation

The area of a semi-circle is found using the formula half times pi times radius squared. Setting this equal to 308 gives half times pi times radius squared equals 308. Using 22 divided by 7 for pi, the equation becomes 11 divided by 7 times radius squared equals 308, so radius squared equals 28 times 7, which is 196. Taking the square root of 196 gives a radius of 14 cm.

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