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What is the total surface area of a hemisphere of radius r?

  • A.4πr²
  • B.πr²
  • C.2πr²
  • D.3πr²

Answer: D

A solid hemisphere has two surfaces: the curved dome and the flat circular base.

\[ \text{curved surface} = 2\pi r^{2}, \qquad \text{flat base} = \pi r^{2} \]

\[ \text{total surface area} = 2\pi r^{2} + \pi r^{2} = 3\pi r^{2} \]

The \( 2\pi r^{2} \) option is the curved surface alone - correct for a hollow bowl, but not for a solid hemisphere, which still has its flat face.

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