Is there proof that any rectangle is a cyclic quadrilateral?
Context: in Euclidean geometry, a cyclic quadrilateral or inscribed quadrilateral is a quadrilateral whose vertices all lie on a single circle. This circle is called the circumcircle or circumscribed circle, and the vertices are said to be concyclic.
Best Answer
Why not just use the property of rectangles that diagonals of rectangle bisect each other?
That will mean that the intersection of diagonals is a point from which all the vertices are equidistant, which means, from the definition of a circle, that they lie on the circle with the center at the intersection.
If you had to prove the property first, you can do it by constructing the two diagonals, intersecting at O, then showing that any two vertically opposite triangles are congruent.