A is a point at a distance 13cm from the center O of a circle of radius 5cm. AP & AQ are the tangents to the circle at P&Q. If the tangent BC is drawn at a pont R lying on the minor arc PQ to intersect AP at B and AQ at C. Find the perimeter of ABC?


BP=BR and CR=CQ  ( length of tangents drawn from an external point to a circle are equal ) 
Perimeter of triangle ABC = AB+BR+RC+CA
=AB+BP+QC+CA
=AP+QA  ( AP=QA)
=2AP  
In triangle APO, by Pythagoras theorem

Perimeter of triangle ABC = cm

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