MathDB
Circle and Triangle

Source:

January 19, 2006
geometrypower of a point

Problem Statement

In the adjoining figure, the circle meets the sides of an equilateral triangle at six points. If AG=2AG=2, GF=13GF=13, FC=1FC=1, and HJ=7HJ=7, then DEDE equals
[asy] size(200); defaultpen(fontsize(10)); real r=sqrt(22); pair B=origin, A=16*dir(60), C=(16,0), D=(10-r,0), E=(10+r,0), F=C+1*dir(120), G=C+14*dir(120), H=13*dir(60), J=6*dir(60), O=circumcenter(G,H,J); dot(A^^B^^C^^D^^E^^F^^G^^H^^J); draw(Circle(O, abs(O-D))^^A--B--C--cycle, linewidth(0.7)); label("AA", A, N); label("BB", B, dir(210)); label("CC", C, dir(330)); label("DD", D, SW); label("EE", E, SE); label("FF", F, dir(170)); label("GG", G, dir(250)); label("HH", H, SE); label("JJ", J, dir(0)); label("2", A--G, dir(30)); label("13", F--G, dir(180+30)); label("1", F--C, dir(30)); label("7", H--J, dir(-30));[/asy]
(A) 222(B) 73(C) 9(D) 10(E) 13\textbf {(A) } 2\sqrt{22} \qquad \textbf {(B) } 7\sqrt{3} \qquad \textbf {(C) } 9 \qquad \textbf {(D) } 10 \qquad \textbf {(E) } 13