Question

If three angles of a quadrilateral are 90° each, show that the given quadrilateral is a rectange.
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Answer 1

The given quadrilateral ABCD will be a rectangle if its each angle is 90°

Since the sum of interior angles is a qadrilateral is 360°

A + B + C +D = 360

90 + 90 + 90 + D = 360

D = 360 - 270

D = 90

Since each angle of the quadrilateral is 90

The given quadrilateral is a rectangle