surface areas

I think you must mean the volume is 250 cm³ not cm²!

The minimum surface area is that of a sphere of that volume.  

Volume of sphere = (4/3)pi*r³   Set this to 250 cm³ to get the radius, r, in cm.

Surface area of sphere = 4pi*r²   Use the radius from the previous step to find the surface area in cm².

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