In Fig 10.57, a circle is inscribed in a quadrilateral ABCD in which . If AD = 23 cm, AB = 29 cm and DS = 5 cm, find the radius r of the circle.



AD = DS = 5cm (tangent from an external point)


Since AD=23 cm


So,


AR + RD + AD


AR + 5 = 23 cm


AR = 18 cm ------(i)


and AQ = AR


since AR = 18 cm


So, AQ + QB = AB


Now OP and OQ are radius of the circle. So from tangent P and Q



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