KGS math club/solution 11 1

There are six ways:

  1. the vertices of a square
  2. the vertices of a 60-degree rhombus
  3. the vertices of an equlateral triangle, plus its midpoint
  4. the vertices of an equlateral triangle, plus a point on a symmetry axis that is a side-length away from the vertex through which that axis passes
  5. the vertices of an equlateral triangle, plus a point on a symmetry axis that is a side-length away, in the opposite direction, from the vertex through which that axis passes
  6. Four of the vertices of a regular pentagon