section_path: Bisecting and trisecting angles
section_name: Bisecting and trisecting angles
paragraph_text: Bisecting and trisecting angles
  
  The ancient Greek mathematicians knew how to bisect an angle (divide it into two angles of equal measure) using only a compass and straightedge but could only trisect certain angles. In 1837, Pierre Wantzel showed that this construction could not be performed for most angles.