Geometry Problem 330: Cyclic quadrilateral, Perpendicular diagonals, Area, Circumcenter - Perfect for High School and College Students!

In the given figure, ABCD is a cyclic quadrilateral with perpendicular diagonals AC and BD. Let O be the circumcenter of ABCD. Prove that the areas of the quadrilaterals ABCO and AOCD are equal

Cyclic quad with lines,
O, the center, awaits proof
Equal areas, shown.