Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2022-part-01 — 197 problems (EN–VI) Question 160

Math Olympiad Vault · MathNet 2022-part-01 — 197 problems (EN–VI)

Question 160

Let $I$ be the incenter of a triangle $ABC$ with $AB \gt AC$, and let $AM$ be the median. The line through $I$ perpendicular to $BC$ meets the line $AM$ at point $L$. Let $J$ be the reflection of $I$ with respect to $A$. Prove that $\angle ABJ = \angle LBI$.