# How Many Diagonals?

- Pause the animation at any point (by clicking the pause button in the bottom left corner).
- Slide the black dot to set the number of sides of the shape you want to investigate.
- Use the check boxes to show/hide all diagonals from a specific vertex.
- Do you see the "triangle number pattern"? Try finding some way of multiplying the number of sides by something to get twice the number of diagonals.

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