Geometrical Solution for the Trisection Problem

The trisection problem date back to the Greeks and Arabs and it is related to the algebraic solution of third degree. It concerns construction of an angle equal to one third of a given arbitrary angle, using only two tools: unmarked ruler and compass. The problem is stated impossible to solve for arbitrary angles, as proved by Pierre Wantzel in 1837. In this article, we present some geometric or algebraic methods to solve the problem from the first one due to Greeks until Maria Gaetana Agnesi’s algebraic-geometric effort. Then we propose a geometric approximation’s method based only on straightedge and compass.