How to prove that the point of intersection of the midpoints of the inscribed quadrilateral ABCD

How to prove that the point of intersection of the midpoints of the inscribed quadrilateral ABCD will be the center of the circumcircle?

Let ABCD be a quadrilateral inscribed in a circle, and points A, B, C, D are on a circle with center O. Restore the midpoint perpendicular to side AB (perpendicular from the middle of AB). Then all points on this perpendicular will be equally distant from points A and B (according to the property of the midpoint perpendicular).

Let us restore the middle perpendicular to the side BC, and all points on it are equally distant from points B and C.
The point of intersection of two perpendiculars will give an equidistant point O from points A, B, and C, OA = OB = OC.

Since point D is also on a circle, then OD = ОА = ОВ = OC = the radius of the circle circumscribed around ABCD. And we found the center of the circle by finding the point of intersection of the median perpendiculars.



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