###### Exercise46

Evaluate

\begin{equation*} \displaystyle \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \end{equation*}

for $$x_1 = 9\text{,}$$ $$x_2 = 18\text{,}$$ $$y_1 = -7\text{,}$$ and $$y_2 = 5\text{:}$$

in-context