The diagonals of quadrilateral \(ABCD\) are equal and bisect each other. One diagonal measures \(24 \ cm\).
(a) If \(O\) is the point of intersection of the diagonals, determine \(OB\). \(cm\)
(Note: Round off the answer to \(1\) decimal place, if required.)
(b) Identify the quadrilateral \(ABCD\).