In figure, a circle touches the side BC of △ABC at P and touches AB and AC produced at Q and R respectively. If AQ = 5 cm, find the perimeter (in cm) of △ABC.
We know that
AQ = AR
AQ = AC + CR
But CR = CP
∴ AQ = AC + CP …..(i)
Also AQ = AB + BQ
But BQ = BP
∴ AQ = AB + BP .….(ii)
Adding equations (i) and (ii)
2AQ = AC + CP + BP + AB
2AQ = Perimeter of △ABC
Perimeter of △ABC = 2 × 5 = 10 cm