[tex]\\ \sf\longmapsto CD=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
[tex]\\ \sf\longmapsto CD=\sqrt{(5+5)^2+(8-4)^2}[/tex]
[tex]\\ \sf\longmapsto CD=\sqrt{(10)^2+(4)^2}[/tex]
[tex]\\ \sf\longmapsto CD=\sqrt{100+16}[/tex]
[tex]\\ \sf\longmapsto CD=\sqrt{116}[/tex]
[tex]\\ \sf\longmapsto CD=10.4[/tex]
