Desargues Configuration
Drag the blue colored point.
If two triangles are so situated that line joining
the pair of corresponding vertices are concurrent then the points of
intersection of pair of corresponding sides are collinear and conversely.
This theorem can be stated as “if two triangles are central couple then they are
axial couple and conversely”.
The Desargues theorem can also be stated as “if
two triangles are perspective from a point then they are perspective from a
line and conversely”.