[tex]\bf ~~~~~~~~~~~~\textit{distance between 2 points}
\\\\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~ 6 &,& 9~)
% (c,d)
&&(~ 10 &,& 15~)
\end{array}~~~
% distance value
d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}
\\\\\\
d=\sqrt{(10-6)^2+(15-9)^2}\implies d=\sqrt{4^2+6^2}\implies d=\sqrt{52}
\\\\\\
d\approx 7.2[/tex]
what's its speed? well, it traveled √(52) in 2 seconds, so is simply √(52)/2, which is about 3.6 units per second.
