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Geometry and Trigonometry / Area and volume Difficulty: Hard

A hemisphere is half of a sphere. If a hemisphere has a radius of 27 inches, which of the following is closest to the volume, in cubic inches, of this hemisphere?

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Explanation

Choice D is correct. The volume, V, of a sphere is given by V=43πr3, where r is the radius of the sphere. Since a hemisphere is half of a sphere, it follows that the volume, V, of a hemisphere is given by V=1243πr3, or V=23πr3. Substituting 27 for r in this formula yields V=23π273, which gives V=13,122π, or V is approximately equal to 41,223.98. Therefore, the choice that is closest to the volume, in cubic inches, of this hemisphere is 41,200.

Choice A is incorrect and may result from conceptual or calculation errors.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice C is incorrect and may result from conceptual or calculation errors.