[tex]d= \sqrt{(x_1 -x_2)^2+(y_1-y_2)^2}= \\ \\
= \sqrt{(-4 -8)^2+(6-(-12))^2}= \\ \\
= \sqrt{(-4 -8)^2+(6+12)^2}= \\ \\
= \sqrt{(-12)^2+(18)^2}= \\ \\
= \sqrt{144+324}= \\ \\
=\sqrt{468}= \sqrt{4 \times 9 \times 13} = \\ \\
= 2\times 3 \sqrt{13} = 6\sqrt{13} =6\times 3.605551=21.63330\approx \boxed{21.63}[/tex]
