Relationship Between Angles
Source:
February 11, 2009
exterior angle
Problem Statement
In circle chord is produced so that equals a radius of the circle. is drawn and extended to . is drawn. Which of the following expresses the relationship between and ?[asy]size(200);defaultpen(linewidth(0.7)+fontsize(10));
pair O=origin, D=dir(195), A=dir(150), B=dir(30), C=B+1*dir(0);
draw(O--A--C--D);
dot(A^^B^^C^^D^^O);
pair point=O;
label("", A, dir(point--A));
label("", B, dir(point--B));
label("", C, dir(point--C));
label("", D, dir(point--D));
label("", O, dir(285));
label("", O+0.1*dir(172.5), dir(172.5));
label("", C+0.4*dir(187.5), dir(187.5));
draw(Circle(O,1));
[/asy]
(A)\ x\equal{}3y \\
(B)\ x\equal{}2y \\
(C)\ x\equal{}60^\circ \\
(D)\ \text{there is no special relationship between }x\text{ and }y \\
(E)\ x\equal{}2y \text{ or }x\equal{}3y\text{, depending upon the length of }AB