Skip to content / Đến nội dung
ThichHocToan.com

AMO 2025 – Secondary 4 (Grade 10) Question 3

AMO · AMO 2025 – Secondary 4 (Grade 10)

Question 3

Three mutually externally tangent circles have centres at the vertices of an equilateral triangle. A large circle encloses them and is internally tangent to all three. A small circle in the central gap is externally tangent to all three. What is the ratio of the large radius to the small radius?

Question illustration
  1. $6+4\sqrt5$
  2. $12-2\sqrt2$
  3. $7+4\sqrt3$
  4. $8+2\sqrt3$