Y by Adventure10, Mango247
Let
be an isosceles triangle, with
. Let
be points on
and
, respectively, such that
is parallel to
and
is parallel to
. Further, let
be the circumcentre of
. Prove that the quadrilateral
is cyclic.












This post has been edited 1 time. Last edited by parmenides51, Jul 21, 2019, 4:31 AM
Reason: typo in the end, the correct is CROQ, I had before CPOQ, thanks below
Reason: typo in the end, the correct is CROQ, I had before CPOQ, thanks below