What regular polygons did Thales know how to build?

Thales knew how to build a regular triangle and a square inscribed in a circle. He could, by drawing the bisectors of the corners, double the number of sides of a regular polygon. But Thales did not know how to build a regular pentagon.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.