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 , , , and , then 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("", A, N);
label("", B, dir(210));
label("", C, dir(330));
label("", D, SW);
label("", E, SE);
label("", F, dir(170));
label("", G, dir(250));
label("", H, SE);
label("", 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]