1. The midpoinst of the small circles form a regular polylateral with the side-length 2r. You have n isosceles triangles.
2. The central angle of one of the isosceles triangles is , that means must be a divisor of 360°.
3. Each isosceles triangle can be split into 2 right triangles with
4. Keep in mind that
An example: You know (from my previous post) that
Now choose a value for which must be a divisor of 180:
To each value of belongs the number of small circles:
Of course you can choose the number of circles first and determine the value of afterwards:
For instance: You want to draw 7 small circles then
But in both cases you have to use the Sine function.