D=d+3
a\sqrt3=a\sqrt2+3
a\sqrt3-a\sqrt2=3
a(\sqrt3-\sqrt2)=3
a=\frac{3}{\sqrt3-\sqrt2}
a=\frac{3(\sqrt3+\sqrt2)}{(\sqrt3-\sqrt2)(\sqrt3+\sqrt2)}
a=\frac{3(\sqrt3+\sqrt2)}{3-2}
a=3(\sqrt3+\sqrt2)[cm]
P=6a^2
P=6*[3(\sqrt3+\sqrt2)]^2=9(3+2*\sqrt6+2)=9(5+2\sqrt6)[cm^2] <-- odpowiedź