[tex]\stackrel{R}{(\stackrel{x_1}{8}~,~\stackrel{y_1}{-8})}\qquad \stackrel{S}{(\stackrel{x_2}{4}~,~\stackrel{y_2}{7})}~\hfill \stackrel{\textit{component form}}{(x_2-x_1~~,~~y_2-y_1)} \\\\[-0.35em] ~\dotfill\\\\ (4-8~~,~~7-(-8))\implies (-4~~,~~7+8)\implies \stackrel{\textit{component form}}{(\underset{a}{-4}~~,~~\underset{b}{15})} \\\\\\ ||RS||=\sqrt{a^2+b^2}\implies ||RS||=\sqrt{(-4)^2+15^2}\implies ||RS||=\sqrt{241}[/tex]
