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 ??

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- Oct 15th 2009, 11:12 PMthereddevilsdeductive 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 AMred_dog
You have to add that $\displaystyle \widehat{QPR}=\widehat{ZPY}$

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