2007 iTest Problems/Problem TB4

Problem

Circle $O$ is the circumcircle of non-isosceles triangle $ABC$ . The tangent lines to circle $O$ at points $B$ and $C$ intersect at $L_a$ , and the tangents at $A$ and $C$ intersect at $L_b$ . The external angle bisectors of triangle $ABC$ at $B$ and $C$ meet at $I_a$ and the external bisectors at $A$ and $C$ intersect at $I_b$ . Prove that lines $L_aI_a$ , $L_bI_b$ , and $AB$ are concurrent.

Solution

2007 iTest (Problems, Answer Key)
Preceded by: Problem TB3	Followed by: Problem Last Question
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2007 iTest Problems/Problem TB4

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