Here are the answers to the questions:
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A quadrilateral whose opposite sides are parallel is called a parallelogram.
Let the quadrilateral be ABCD.
Given: AB∥CD and AD∥BC.
Therefore, ABCD is a parallelogram.
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A quadrilateral with all sides equal and each angle is 90∘ is a square.
Let the quadrilateral be PQRS.
Given: PQ=QR=RS=SP and ∠P=∠Q=∠R=∠S=90∘.
Therefore, PQRS is a square.
That's 2 down. 3 left today — send the next one.