11. The axiom was part of Pasch's approach to introducing the concept of order into plane geometry . 12. Forget plane geometry , I was plain scared. 13. The proof demonstrates the power of the algebra of complex numbers in handling problems in plane geometry . 14. The resulting structure, a model of elliptic geometry, satisfies the axioms of plane geometry except the parallel postulate. 15. In Euclidean plane geometry , the "'van Lamoen circle "'is a special circle associated with any given triangle T. 16. Unlike the square of plane geometry , the angles of such a square are larger than a right angle. 17. He is also honoured by having the Cartesian coordinate system used in plane geometry and algebra named after him. 18. In Euclidean plane geometry terms, being a parallelogram is affine since affine transformations always take one parallelogram to another one. 19. Cayley Klein plane geometry depends upon the selection of a conic that becomes the " absolute " of the space. 20. :: Since when do centimeters figure into plane geometry ? ?! carrots 23 : 49, 6 October 2009 ( UTC)
