Answer:
Step-by-step explanation:
taking A(3, 3), B(6, 6), C(9,3) and D(6,0)
we have: [tex]y_A=y_C\quad and\quad x_B=x_D[/tex] so the AC and BD are diagonals, that means:
AB = BC = CD = DA = s
[tex]s=\sqrt{(6-3)^2+(6-3)^2}=\sqrt{3^2+3^2}=\sqrt{18}\\\\\\A=s^2=(\sqrt{18})^2=18[/tex]