well, since we know that
B (-1 , -1) and A (3 , 1), then
[tex]~~~~~~~~~~~~\textit{distance between 2 points} \\\\ B(\stackrel{x_1}{-1}~,~\stackrel{y_1}{-1})\qquad A(\stackrel{x_2}{3}~,~\stackrel{y_2}{1})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ BA=\sqrt{[3 - (-1)]^2 + [1 - (-1)]^2}\implies BA=\sqrt{(3+1)^2+(1+1)^2} \\\\\\ BA=\sqrt{4^2+2^2}\implies BA=\sqrt{20}\implies BA\approx 4.5[/tex]
