We can create a diagram to solve this question.
As we see, this creates a square where the intersection occurs. I'll add a red line to illustrate the triangle we are going to make.
We know that both legs of the triangle are going to be 6 meters. We need to find the hypotenuse of the triangle, which we are going to do by using Pythagorean's Theorem.
[tex]\begin{gathered} 6^2_{}+6^2=c^2 \\ 36+36=c^2 \\ \sqrt[]{64}=\sqrt[]{c^2} \\ c=8 \end{gathered}[/tex]Therefore, the distance between two opposite corners of the intersection is 8 meters.