A quadrilateral ABCD is drawn to circumscribe a circle prove that AB +

1.	A quadrilateral ABCD is drawn to circumscribe a circle prove that AB + CD is equals to ad + Bc
Answer» Since, tangents drawn from an exterior point to a circle are equal in length.∴ AP = AS ...(i)BP = BQ ...(ii)CR = CQ ...(iii)and DR = DS ...(iv)Adding (i), (ii), (iii) and (iv), we getAP + BP + CR + DR = AS + BQ + CQ + DS⇒ (AP + BP) + (CR + DR)= (AS + DS) + (BQ + CQ)⇒ AB + CD = AD + BCHence, AB + CD = BC + DA.

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