9. Given a regular param1. Find the number of its vertex quadruples that are vertices of a convex quadrilateral with exactly two angles equal to $90^{\circ}$. (Two quadruples of vertices that differ in the order of vertices are considered the same.)

| param1 |  |
| :---: | :---: |
| 16-gon |  |
| 18-gon |  |
| 20-gon |  |
| 14-gon |  |
9. Given a regular param1. Find the number of its vertex quadruples that are vertices of a convex quadrilateral with exactly two angles equal to $90^{\circ}$. (Two quadruples of vertices that differ in the order of vertices are considered the same.)

| param1 | Answer |
| :---: | :---: |
| 16-gon | 336 |
| 18-gon | 504 |
| 20-gon | 720 |
| 14-gon | 210 |