Multiple choice

If the curved surface area of a hemisphere is 2772 $cm^2$, then its diameter is -

  1. 42 cm

  2. 21 cm

  3. 20 cm

  4. 40 cm
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A Correct answer
Explanation

Curved surface area of a hemisphere is 2 * pi * r^2. 2 * (22/7) * r^2 = 2772. r^2 = 2772 * 7 / 44 = 441. r = 21. Diameter = 2 * r = 42 cm.

AI explanation

The curved surface area of a hemisphere is given by the formula 2*pi*r^2. We set this equal to 2772, so 2*(22/7)*r^2 = 2772. Solving for r^2 gives 441, which means the radius r is 21 cm. The diameter is twice the radius, so the diameter is 42 cm.

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