1989 APMO Problems/Problem 3

Revision as of 21:56, 11 July 2021 by Satisfiedmagma (talk | contribs) (Created page with "==Problem== Let <math>A_1</math>, <math>A_2</math>, <math>A_3</math> be three points in the plane, and for convenience, let <math>A_4= A_1</math>, <math>A_5 = A_2</math>. For...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Problem

Let $A_1$, $A_2$, $A_3$ be three points in the plane, and for convenience, let $A_4= A_1$, $A_5 = A_2$. For $n = 1$, $2$, and $3$, suppose that $B_n$ is the midpoint of $A_n A_{n+1}$, and suppose that $C_n$ is the midpoint of $A_n B_n$. Suppose that $A_n C_{n+1}$ and $B_n A_{n+2}$ meet at $D_n$, and that $A_n B_{n+1}$ and $C_n A_{n+2}$ meet at $E_n$. Calculate the ratio of the area of triangle $D_1 D_2 D_3$ to the area of triangle $E_1 E_2 E_3$.

Solution