Page "Blaise Pascal" Paragraph 6

Particularly of interest to Pascal was a work of Desargues on conic sections.

Following Desargues ' thinking, the sixteen-year-old Pascal produced, as a means of proof, a short treatise on what was called the " Mystic Hexagram ", Essai pour les coniques (" Essay on Conics ") and sent it — his first serious work of mathematics — to Père Mersenne in Paris ; it is known still today as Pascal's theorem.

It states that if a hexagon is inscribed in a circle ( or conic ) then the three intersection points of opposite sides lie on a line ( called the Pascal line ).