[tex]\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ A(\stackrel{x_1}{4}~,~\stackrel{y_1}{5})\qquad B(\stackrel{x_2}{7}~,~\stackrel{y_2}{-9})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ AB=\sqrt{(7-4)^2+(-9-5)^2}\implies AB=\sqrt{3^2+(-14)^2} \\\\\\ AB=\sqrt{9+196}\implies AB=\sqrt{205}\implies AB\approx 14.32[/tex]