The quadrilateral formed by joining the midpoints of the sides of a quadrilateral ABCD, taken in order, is a rhombus, if
(a) ABCD is a parallelogram
(b) ABCD is a rhombus
(c) diagonals of ABCD are equal
(d) diagonals of ABCD are perpendicular to each other
The figure formed by joining the midpoints of the sides of a quadrilateral ABCD, taken in order, is a square, only if
(a) ABCD is a rhombus
(b) diagonals of ABCD are equal
(c) diagonals of ABCD are perpendicular
(d) diagonals of ABCD are equal and perpendicular
The quadrilateral formed by joining the midpoints of the sides of a quadrilateral ABCD, taken in order, is a rectangle, if
(b) ABCD is a rectangle
In a quadrilateral ABCD, suppose AB = CD and AD = BC. Prove that ABCD is a parallelogram.