Two circles intersect each other at points P and Q. If AB and AC are the tangents to the circles from a point A on QP produced show that AB=AC

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We know that,
If a tangent segment and a secant intersect in the exterior of a circle, then the square of a length of the tangent segment is equal to the product of the length of the secant segments and its exterior part.


Since AB is tangent and APQ is a secant. Therefore,
AB2=AQ×AP                                    .....1
Similarly, AC is tangent and APQ is a secant. So,
AC2=AQ×AP                                    .....2
From (1) and (2),  we have,
AB2=AC2AB=ACHence Proved.

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