How do i prove that a quadrilateral is a rectangle? (in a column chart with statement and reason)

By definition, we have to:

 In plane geometry, a rectangle is a parallelogram whose four sides are at right angles to each other. Opposite sides have the same length.

 There is a proof that a quadrilateral is a rectangle:

  1) Its parallel sides are the same.

 2) Its two diagonals are the same, and they bisect each other at the common midpoint

 3) Any rectangle can be inscribed in a circle, two of whose diameters coincide with the diagonals of the rectangle.

 4) If all the angles of a quadrilateral are right angles, then it is a rectangle

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