[tex]|AB|=\sqrt{(x_{b}-x_{a})^2+(y_b-y_a)^2}\\|AC|=\sqrt{(x_{c}-x_{a})^2+(y_c-y_a)^2}\\|BC|=\sqrt{(x_{c}-x_{b})^2+(y_c-y_b)^2}\\ \\ \\|AB|= \sqrt{(3+1)^2+(-1+5)^2}=\sqrt{32}=4\sqrt{2}\\|AC|=\sqrt{(2+1)^2+(4+5)^2}=\sqrt{90}=3\sqrt{10}\\|BC|=\sqrt{(3-2)^2+(4+1)^2}=\sqrt{26}\\\\Obw.=4\sqrt{2}+3\sqrt{10}+\sqrt{26}[/tex]
