Angle Trisection -- from Wolfram MathWorld
Angle trisection is the division of an arbitrary angle into three equal angles. It was one of the three geometric problems of antiquity for which solutions using only compass and straightedge were sought. The problem was algebraically proved impossible by Wantzel (1836). Although trisection is not possible for a general angle using a Greek construction, there are some specific angles, such as pi/2 and pi radians (90 degrees and 180 degrees, respectively), which can be trisected. Furthermore
Angle Trisection: A Math Problem Claimed to Not be Solvable and Has Not Been Solved for Over 2200 Years is Solved by Mahesh Bubna in 2022
Angle Trisection Different Modes, PDF, Circle
Angle trisection - Wikipedia
Equal Parallelians Point -- from Wolfram MathWorld
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Wolfram Mathworld in the Notebook Archive
Angle Trisection -- from Wolfram MathWorld
Angle - Wikipedia
Trisection of angles-similarly
Measure of the Angle between Two Straight Lines - Wolfram Demonstrations Project
PDF) A Classical Proof on the Constructability of Geometric Magnitudes: In the Case of Angles (Reconsidering the Angle Trisection Problem, a Comprehensive Survey)
Can a regular hendecagon be drawn with only a compass, straightedge, and angle quintisector? If so, why exactly? - Quora
Wolfram Mathworld in the Notebook Archive
Angle Trisection Different Modes, PDF, Circle