jika volume kubus 27 cm³,panjang diagonal sidi kubus adalah..

Vol = s³ = 27 mk s=3 cm
Diagonal sisi = s√2 = 3√2 cm

Jika rusuk = s
volume = s³ ( s x s x s) = 27
                s = ∛27 = 3
Rumus diagonal sisi = s√2 = 3√2