sentences:  Geometrically, we have intersected the circle "x"2 + "y"2 = "a"2 with the line "y" = "tx" - "a", as shown in the adjacent diagram.Writing the lengths, OB, OA, and AB, of the sides of triangle OAB as an ordered tuple, we obtain the triple
  
  The specific result obtained by Diophantus may be obtained by taking "a" = 4 and "t" = 2