Odpowiedź:
[tex]A=(-20,0)\ \ \ \ B=(20,-40)\\\\Obliczamy\ \ dlugo\'s\'c\ \ jednego\ \ boku\ \ kwadratu\\\\|AB|=\sqrt{(x_{B}-x_{A})^2+(y_{B}-y_{A})^2}=\sqrt{(20-(-20))^2+(-40-0)^2}=\\\\=\sqrt{(20+20)^2+(-40)^2}=\sqrt{40^2+40^2}=\sqrt{2\cdot40^2}=\sqrt{2}\cdot\sqrt{40^2}=40\sqrt{2}\\\\\\Obliczam\ \ obw\'od\ \ kwadratu\\\\Ob=4\cdot|AB|=4\cdot40\sqrt{2}=160\sqrt{2}[/tex]
