Proofs of Existence and Optimality · Proofs of Optimality
Lesson 6
Finally, let's consider a more complex problem.
Problem. In each of the twenty-five squares of a \(5\times 5\) grid, a diagonal can be drawn in one of two ways. What is the maximum number of diagonals that can be drawn so that no two have common points? Try it!
Below are two examples of arrangements with thirteen and fifteen diagonals.

5 points