MathDB
Square geometry

Source: 2009 SDMO Middle School Problem 2

August 24, 2016
ratiogeometry

Problem Statement

Let ABCDABCD be a square, and let EE and FF be points on sides AB\overline{AB} and CD\overline{CD}, respectively, such that AE:EB=AF:FD=2:1AE:EB=AF:FD=2:1. Let GG be the intersection of AF\overline{AF} and DE\overline{DE}, and let HH be the intersection of BF\overline{BF} and CE\overline{CE}. Find the ratio of the area of quadrilateral EGFHEGFH to the area of square ABCDABCD.
[asy] size(5cm,0); draw((0,0)--(3,0)); draw((3,0)--(3,3)); draw((3,3)--(0,3)); draw((0,3)--(0,0)); draw((0,0)--(2,3)); draw((1,0)--(3,3)); draw((0,3)--(1,0)); draw((2,3)--(3,0)); label("AA",(0,3),NW); label("BB",(3,3),NE); label("CC",(3,0),SE); label("DD",(0,0),SW); label("EE",(2,3),N); label("FF",(1,0),S); label("GG",(0.66666667,1),E); label("HH",(2.33333333,2),W); [/asy]