MathDB
2013/8/24/Three squares

Source:

November 27, 2013
ratiogeometryrectanglerotationAMC

Problem Statement

Squares ABCDABCD, EFGHEFGH, and GHIJGHIJ are equal in area. Points CC and DD are the midpoints of sides IHIH ad HEHE, respectively. What is the ratio of the area of the shaded pentagon AJICBAJICB to the sum of the areas of the three squares?
[asy] pair A,B,C,D,E,F,G,H,I,J; A = (0.5,2); B = (1.5,2); C = (1.5,1); D = (0.5,1); E = (0,1); F = (0,0); G = (1,0); H = (1,1); I = (2,1); J = (2,0); draw(A--B); draw(C--B); draw(D--A); draw(F--E); draw(I--J); draw(J--F); draw(G--H); draw(A--J); filldraw(A--B--C--I--J--cycle,grey); draw(E--I); dot("AA", A, NW); dot("BB", B, NE); dot("CC", C, NE); dot("DD", D, NW); dot("EE", E, NW); dot("FF", F, SW); dot("GG", G, S); dot("HH", H, N); dot("II", I, NE); dot("JJ", J, SE);[/asy]
<spanclass=latexbold>(A)</span> 14<spanclass=latexbold>(B)</span> 724<spanclass=latexbold>(C)</span> 13<spanclass=latexbold>(D)</span> 38<spanclass=latexbold>(E)</span> 512<span class='latex-bold'>(A)</span>\ \frac14 \qquad <span class='latex-bold'>(B)</span>\ \frac7{24} \qquad <span class='latex-bold'>(C)</span>\ \frac13 \qquad <span class='latex-bold'>(D)</span>\ \frac38 \qquad <span class='latex-bold'>(E)</span>\ \frac5{12}