Rumfang=4/3·π·r^3 R u m f a n g = 4 3 ⋅ π ⋅ r 3
Overflade=4·π·r^2O v e r f l a d e = 4 ⋅ π ⋅ r 2
r=√(3&(Rumfang·3/(4·π)))r = Rumfang ⋅ 3 4 ⋅ π 3
Eller
r=√(Overflade/(4·π)) r = O v e r f l a d e 4 ⋅ π
