Difference between revisions of "2015 AMC 8 Problems/Problem 2"

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<math>\textbf{(A) }\frac{11}{32} \quad\textbf{(B) }\frac{3}{8} \quad\textbf{(C) }\frac{13}{32} \quad\textbf{(D) }\frac{7}{16}\quad \textbf{(E) }\frac{15}{32}</math>
 
<math>\textbf{(A) }\frac{11}{32} \quad\textbf{(B) }\frac{3}{8} \quad\textbf{(C) }\frac{13}{32} \quad\textbf{(D) }\frac{7}{16}\quad \textbf{(E) }\frac{15}{32}</math>
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<asy>
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pair A,B,C,D,E,F,G,H,O,X;
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A=dir(45);
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B=dir(90);
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C=dir(135);
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D=dir(180);
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E=dir(-135);
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F=dir(-90);
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G=dir(-45);
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H=dir(0);
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O=(0,0);
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X=midpoint(A--B);
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fill(X--B--C--D--E--O--cycle,rgb(0.75,0.75,0.75));
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draw(A--B--C--D--E--F--G--H--cycle);
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dot("$A$",A,dir(45));
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dot("$B$",B,dir(90));
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dot("$C$",C,dir(135));
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dot("$D$",D,dir(180));
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dot("$E$",E,dir(-135));
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dot("$F$",F,dir(-90));
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dot("$G$",G,dir(-45));
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dot("$H$",H,dir(0));
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dot("$X$",X,dir(135/2));
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dot("$O$",O,dir(0));
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draw(E--O--X);
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</asy>

Revision as of 15:30, 25 November 2015

Point $O$ is the center of the regular octagon $ABCDEFGH$, and $X$ is the midpoint of the side $\overline{AB}.$ What fraction of the area of the octagon is shaded?

$\textbf{(A) }\frac{11}{32} \quad\textbf{(B) }\frac{3}{8} \quad\textbf{(C) }\frac{13}{32} \quad\textbf{(D) }\frac{7}{16}\quad \textbf{(E) }\frac{15}{32}$

[asy] pair A,B,C,D,E,F,G,H,O,X; A=dir(45); B=dir(90); C=dir(135); D=dir(180); E=dir(-135); F=dir(-90); G=dir(-45); H=dir(0); O=(0,0); X=midpoint(A--B);  fill(X--B--C--D--E--O--cycle,rgb(0.75,0.75,0.75)); draw(A--B--C--D--E--F--G--H--cycle);  dot("$A$",A,dir(45)); dot("$B$",B,dir(90)); dot("$C$",C,dir(135)); dot("$D$",D,dir(180)); dot("$E$",E,dir(-135)); dot("$F$",F,dir(-90)); dot("$G$",G,dir(-45)); dot("$H$",H,dir(0)); dot("$X$",X,dir(135/2)); dot("$O$",O,dir(0)); draw(E--O--X); [/asy]