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ITOT 45 Spring 2024 · THPT · A (Advanced) Question 4

ITOT · ITOT 45 Spring 2024 · THPT · A (Advanced)

Question 4

Two equal circles$\omega_1,\omega_2$ have centers$O_1,O_2$. Points$X,Y$ lie on segment$O_1O_2$ with$O_1Y=O_2X$. Points$A,B$ lie on$\omega_1$ and line$AB$ passes through$X$; points$C,D$ lie on$\omega_2$ and line$CD$ passes through$Y$. Prove that a circle tangent to all four lines$AO_1,BO_1,CO_2,DO_2$ exists.

The source’s assertion is preserved. Its unrestricted wording has a counterexample, explained in the editor-authored solution rather than silently adding a hypothesis.

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