Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2016-part-06 — 184 problems (EN–VI) Question 147

Math Olympiad Vault · MathNet 2016-part-06 — 184 problems (EN–VI)

Question 147

Triangle **ABC** is such that $\angle ABC = \angle ACB = 30^\circ$. On the side **BC** point **D** is selected. The point **K** is such that **D** is the midpoint of **AK**. It turned out that $\angle BKA \gt 60^\circ$. Prove that $3AD \lt CB$.