\[ d = \sqrt {{{({x_1} - {x_2})}^2} + {{({y_1} - {y_2})}^2} + {{({z_1} - {z_2})}^2}} \]
Where :
\[ c = \sqrt {{a^2} + {b^2}} \]
Where :
\[ (x,y) = \left( {\frac{{m{x_2} \pm n{x_1}}}{{m \pm n}},\frac{{m{y_2} \pm n{y_1}}}{{m \pm n}}} \right)\]
Where :