6.ABC is a right-angled triangle and O is the midpoint of the side opposite to the right angle. Explain why O is equidistant from A, B and C. (The dotted lines are drawn additionally to help you).

Since the right-angled triangle ABC makes a rectangle ABCD by the dotted lines. Therefore OA = OB = OC = OD as the diagonals of a rectangle are equal and bisect each other.Hence, O is equidistant from A, B and C.