Answer :
[tex]\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ K(\stackrel{x_1}{-7}~,~\stackrel{y_1}{5})\qquad H(\stackrel{x_2}{5}~,~\stackrel{y_2}{7})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ KH=\sqrt{[5-(-7)]^2+[7-5]^2}\implies KH=\sqrt{(5+7)^2+(7-2)^2} \\\\\\ KH=\sqrt{144+4}\implies KH=\sqrt{148}\implies KH\approx 12.17[/tex]