Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2025-part-01 — 187 problems (EN–VI) Question 73

Math Olympiad Vault · MathNet 2025-part-01 — 187 problems (EN–VI)

Question 73

In the scalene triangle $ABC$, the in-circle touches side *BC* at the point *D*. The angle bisectors of $\angle ABC$ and $\angle ACB$ meet the circumcircle of the triangle at the points $T_B$ and $T_C$, respectively. Let $AX_B$ and $AX_C$ be diameters in the circumcircles of triangles $ACD$ and $ABD$, respectively. Prove that the triangles $BT_CX_C$ and $CT_BX_B$ are similar.