**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 r**

**(b) diagonals of ABCD are equal**

**(c) diagonals of ABCD are perpendicular to each other**

**(d) diagonals of ABCD are equal and perpendicular to each other.**

**Solution:**

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