Double perspective triangles
Double perspective triangles
Two triangles in double perspective are in triple perspective
Let and
be in double perspective, which means that triples of lines
and
are concurrent. Prove that lines
and
are concurrent (the triangles are in triple perspective).
Proof
Denote
It is known that there is projective transformation that maps any quadrungle into square. We use this transformation for . We use the claim and get the result: lines
and
are concurrent.