Math CentralQuandaries & Queries


Question from Caitlin:

Why does the surface area formula of a sphere have a squared radius while the volume of a sphere has a cubed radius?

Hi Caitlin,

The surface of a sphere is a two-dimensional object so if your measuring the radius in inches then an area will be measured in square inches. Hence the formula for area must have units of inches squared. Likewise the volume is in cubic inches so you need an $r^3$ factor in the formula.

I hope this helps,

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