[tex]P = 48 \ cm^{2}\\oraz\\ P = a^{2}\\\\a^{2} = 48 \ cm^{2}}\\\\a = \sqrt{48} = \sqrt{16\cdot3} = \sqrt{16}\cdot\sqrt{3} = 4\cdot\sqrt{3} = 4\sqrt{3}\\\\\underline{a = 4\sqrt{3} \ cm}\\\\d = a\sqrt{2}\\\\d = 4\sqrt{3}\cdot\sqrt{2} = 4\sqrt{3\cdot2} \ cm\\\\\boxed{d = 4\sqrt{6} \ cm}\\\\\underline{Odp. \ C.}[/tex]
