What are the different ways you can show that three points are collinear ?View attachment 30412
These are two secants circles in A and B such as the radii [OA] and [O'A] are perpendicular. M belongs to one circle and C and D are repectively the intersections of (MA) and (MB) with the other circle
Show that C, D and O' are aligned.
No.Fo DO'C to be a straight line you need to show that MDC is a triangle i.e the angles must sum to 180 deg. Start from there.
Also, the important identity in this scenario is that the line between the intersection points AB is a perpendicular bisector to the line between the centres OO'