Perspective (geometry)
In geometry, two triangles are perspective (or homologic) if, when the sides of each triangle are extended, they meet at three collinear points. The line which goes through the three points is known as the perspectrix, perspective axis, homology axis, or axis of perspectivity. The triangles are said to be perspective from the line.[1] The point at which the lines joining the vertices of the perspective triangle intersect is called the perspector, perspective center, homology center, pole, or center of perspectivity.
Karl von Staudt introduced the notation 
for the relation of triangles ABC and abc.[2]
See also
References
- ^ Weisstein, Eric W., "Perspective Triangles" from MathWorld.
- ^ Coxeter 1942 21,2
- H. S. M. Coxeter (1942) Non-Euclidean Geometry, University of Toronto Press, reissued 1998 by Mathematical Association of America, ISBN 0-88385-522-4 .