Concentric Squares
Source:
January 5, 2007
geometryperimeterAMCAIMEnumber theoryrelatively primeAIME I
Problem Statement
The two squares shown share the same center and have sides of length 1. The length of is and the area of octagon is where and are relatively prime positive integers. Find
[asy]
real alpha = 25;
pair W=dir(225), X=dir(315), Y=dir(45), Z=dir(135), O=origin;
pair w=dir(alpha)*W, x=dir(alpha)*X, y=dir(alpha)*Y, z=dir(alpha)*Z;
draw(W--X--Y--Z--cycle^^w--x--y--z--cycle);
pair A=intersectionpoint(Y--Z, y--z),
C=intersectionpoint(Y--X, y--x),
E=intersectionpoint(W--X, w--x),
G=intersectionpoint(W--Z, w--z),
B=intersectionpoint(Y--Z, y--x),
D=intersectionpoint(Y--X, w--x),
F=intersectionpoint(W--X, w--z),
H=intersectionpoint(W--Z, y--z);
dot(O);
label("", O, SE);
label("", A, dir(O--A));
label("", B, dir(O--B));
label("", C, dir(O--C));
label("", D, dir(O--D));
label("", E, dir(O--E));
label("", F, dir(O--F));
label("", G, dir(O--G));
label("", H, dir(O--H));[/asy]