section_path: Geometric constructibility
section_name: Geometric constructibility
paragraph_text: Geometric constructibility
  
  The ancient Greek mathematicians knew how to use compass and straightedge to construct a length equal to the square root of a given length, when an auxiliary line of unit length is given. In 1837 Pierre Wantzel proved that an n th root of a given length cannot be constructed if n is not a power of 2.