Given the information on the problem, we have the following diagram:
since we want the distance between the two opposite corners of the intersection, we have the following:
then, we can find the missing distance using the pythagorean theorem:
[tex]\begin{gathered} x=\sqrt[]{(15)^2+(8)^2}=\sqrt[]{225+64}=\sqrt[]{289}=17 \\ \Rightarrow x=17m \end{gathered}[/tex]therefore, the distance between the two opposite corners of the intersection is 17 m