ABCD is a parallelogram whose diagonals AC and BD intersect at O.
(i) Show that △AOB≅△COD and name the congruence criterion used.
(ii) Using the result of part (i), prove that OA=OC and OB=OD.
(iii) What do you conclude about point O with respect to the diagonals AC and BD? Give a brief proof for your conclusion.