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The surface area of a sphere is $3627_w38_h13.png$. $9965_w23_h16.png$ . What is the sphere’s diameter, in inches?

A 20

Using the formula for the surface area of a sphere from the formula sheet (and omitting the units), solve $6132_w98_h17.png$ for r
The diameter is twice the length of r, so the sphere’s diameter is 20 inches. (–10 is also a solution, but it is rejected because r cannot be negative.)