Multiple choice

The curved surface area of a hemisphere is $77 cm^2$. The radius of the hemisphere is :

  1. $3.5 cm$
  2. $7cm$
  3. $10.5cm$
  4. $11cm$
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A Correct answer
Explanation

The curved surface area of a hemisphere is 2 * pi * r^2. Given 2 * pi * r^2 = 77, r^2 = 77 / (2 * 3.14159) = 12.25. r = sqrt(12.25) = 3.5 cm.

AI explanation

The curved surface area of a hemisphere is half the surface area of a sphere, given by the formula 2 * pi * r^2. Equating this to the given area gives 2 * pi * r^2 = 77. Solving for r^2 gives 77 / (2 * 22/7), which simplifies to 49/4, meaning the radius r is the square root of 49/4, or 3.5 cm.

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