Distance formula
[tex]\boxed{\sf AB=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}}[/tex]
[tex]\\ \sf\longmapsto \sqrt{(6 - 0) {}^{2} + {(8 - 0)}^{2} } \\ \\ \sf\longmapsto \sqrt{ {6}^{2} + {8}^{2} } \\ \\ \sf\longmapsto \sqrt{36 + 64 } \\ \\ \sf\longmapsto \sqrt{100} \\ \\ \sf\longmapsto 10[/tex]