MathDB
Angles in Minor Arcs

Source: 2015 AIME I Problem 6

March 20, 2015
AMCAIMEAIME I

Problem Statement

Point A,B,C,D,A,B,C,D, and EE are equally spaced on a minor arc of a circle. Points E,F,G,H,IE,F,G,H,I and AA are equally spaced on a minor arc of a second circle with center CC as shown in the figure below. The angle ABD\angle ABD exceeds AHG\angle AHG by 1212^\circ. Find the degree measure of BAG\angle BAG.[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("AA",A,dir(0)); label("BB",B,dir(75)); label("CC",C,dir(90)); label("DD",D,dir(105)); label("EE",E,dir(180)); label("FF",F,dir(225)); label("GG",G,dir(260)); label("HH",H,dir(280)); label("II",I,dir(315)); [/asy]