A quadrilater ABCD is draw to circumscribe a circle

1.	A quadrilater ABCD is draw to circumscribe a circle
Answer» Let ABCD be the quadrilateral circumscribing a circle with centre O.The quadrilateral touches the circle at point P Q R S To prove : AB+ CD= AD+ BCProof: from theorem 10.2 we get the tangents drawn from external point on circle are equalHence, AP=PS .....1BP= BQ.....2CR=CQ........3DR=DS....... 4Adding 1, 2,3 and 4 we getAB+BP+CR+DR=PS+BQ+CQ+D\'SAB+CD=AD+BC Hence proof.

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