Multiple choice

A right circular cylinder just encloses a sphere of radius $r$. Find surface area of the sphere.

  1. $4\pi{r}^{2}$
  2. $2\pi{r}^{2}$
  3. $\pi{r}^{2}$
  4. $3\pi{r}^{2}$
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A Correct answer
Explanation

A sphere enclosed in a cylinder has the same radius r. The surface area of the sphere is 4 * pi * r^2.

AI explanation

When a right circular cylinder just encloses a sphere of radius r, the sphere touches the top, bottom, and lateral sides of the cylinder. The surface area of any sphere is determined by the standard geometric formula 4 times pi times r squared. Therefore, the surface area of the enclosed sphere is 4 times pi times r squared.

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