Angles in Minor Arcs
Source: 2015 AIME I Problem 6
March 20, 2015
AMCAIMEAIME I
Problem Statement
Point and are equally spaced on a minor arc of a circle. Points and are equally spaced on a minor arc of a second circle with center as shown in the figure below. The angle exceeds by . Find the degree measure of .[asy]
pair A,B,C,D,E,F,G,H,I,O;
O=(0,0);
C=dir(90);
B=dir(70);
A=dir(50);
D=dir(110);
E=dir(130);
draw(arc(O,1,50,130));
real x=2*sin(20*pi/180);
F=x*dir(228)+C;
G=x*dir(256)+C;
H=x*dir(284)+C;
I=x*dir(312)+C;
draw(arc(C,x,200,340));
label("",A,dir(0));
label("",B,dir(75));
label("",C,dir(90));
label("",D,dir(105));
label("",E,dir(180));
label("",F,dir(225));
label("",G,dir(260));
label("",H,dir(280));
label("",I,dir(315));
[/asy]