the difference between "k" and "g" is also the distance between them
thus [tex]\bf \textit{distance between 2 points}\\ \quad \\
\begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
%  (a,b)
k&({{ -2}}\quad ,&{{ -1}})\quad 
%  (c,d)
g&({{ 2}}\quad ,&{{ 8}})\\\\
\end{array}\qquad 
%  distance value
d = \sqrt{({{ x_2}}-{{ x_1}})^2 + ({{ y_2}}-{{ y_1}})^2}\\\\
-----------------------------\\\\
kg=\sqrt{[2-(-2)]^2+[8-(-1)]^2}[/tex]