In the adjoining figure, `triangle ABC` is a triangle and through A, B, C lines drawn, parallel respectively to BC, CA and AB, intersecting at P, Q and R. Prove that the perimeter of `triangle PQR` is double the perimeter of `triangle ABC.`

Explanation

As poved in prev. questions: `BC=(1)/(2)QR, CA=(1)/(2)PQ, AB=(1)/(2)PR`
`rArr AB+BC+CA=(1)/(2)(PR+QR+PQ).`