# deductive geo

• Oct 15th 2009, 11:12 PM
thereddevils
deductive geo
The diagram shows the triangle PQR with sides PQ and PR produced to Y and Z respectively so that PQ . PY=PR . PZ . Prove that triangles PQR and PZY are similar .

PQ/PZ=PR/PY

is this sufficient to prove that they are similar ??
• Oct 16th 2009, 12:54 AM
red_dog
You have to add that $\widehat{QPR}=\widehat{ZPY}$

In this case QR is known as an "antiparallel" to YZ.