
\begin{question}
What is the distance between the two points
$p = (2, 4)$ and $q = (5, 4)$
in a Cartesian coordinate system?
\end{question}

\begin{solution}
The distance $d$ of $p$ and $q$ is given by
$d^2 = (p_1 - q_1)^2 + (p_2 - q_2)^2$ (Pythagorean formula).

Hence $d = \sqrt{(p_1 - q_1)^2 + (p_2 - q_2)^2} =
  \sqrt{(2 - 5)^2 + (4 - 4)^2}
   = 3$.

\includegraphics{dist-002}
\end{solution}

%% \extype{num}
%% \exsolution{3}
%% \exname{Euclidean distance}
%% \extol{0.01}
