ABCD=patrat
AB=6[tex] \sqrt{2} [/tex]
BD=?
AB, BC, CD, DA=6[tex] \sqrt{2} [/tex]
Unim B cu D, adica ducem diagonala. => triunghiul dreptunghic BCD
BC, CD catete, DB=?
DB[tex] DB^{2} [/tex]= [tex] BC^{2} + CD^{2} [/tex]
DB[tex] DB^{2} [/tex]= [tex]6 \sqrt{2}^{2} + 6 \sqrt{2}^{2} [/tex]
DB patrat=144=> radical din 144 este 12, deci DB=12
