Online Geometry Problem 788: Intersecting Circles, Secant Line,
Midpoint, Cyclic Quadrilateral. Level: High School,
SAT Prep, College,
Mathematics Education

In the figure below, the circles O and Q intersect at A and B.
G is the midpoint of a secant line CAD, H is the midpoint of a secant
line EAF. Prove that AHBG is a cyclic quadrilateral.