N can be 2, 3, 4, 6, 12.

First of all, a 45 triangle can divide the circumference into 2, 4 and 8 equal parts. 2 and 4 equal parts can divide a regular hexagon into a trapezoid with the same area, but 8 equal parts can't find a regular hexagon.

In addition, because a 60-degree triangle can be divided into two 30-degree triangles with equal circumferential angles, we only consider the 30-degree triangle.

Can divide the circumferential angle into 2, 3, 4, 6, 12 equal parts, and verify that the area of a regular hexagon can be divided equally in these five equal parts.

We find that a 45-degree triangle divides the region into two or four parts, which is included in the case of a 30-degree triangle.

2. The original formula = (a 2-1)/a * a/(a-1) 2.

? =(a+ 1)(a- 1)/a * a/(a- 1)^2

? =(a+ 1)/(a- 1)