Problem:
Determine the number of convex polygons all of whose sides are the square roots of positive integers which can be inscribed in a unit circle. Polygons that are rotations or reflections of each other are considered the same.
Problem:
Determine the number of convex polygons all of whose sides are the square roots of positive integers which can be inscribed in a unit circle. Polygons that are rotations or reflections of each other are considered the same.
Solution:
Any chord in a unit circle has length at most (if it is a diameter), so all side lengths must be , , , or . We can do casework based on the number of sides:
- Triangles: The possible combinations of side lengths are , , , and . This is possibilities.
- Quadrilaterals: The possible ordered combinations of side lengths are , , , , , and . This is possibilities.
- Pentagons: The possible combinations of side lengths are , , and . This is possibilities.
- Hexagons: The only option is that all sides are , so there is possibility.
Putting these together, there are polygons total.