Question

Complete a 2 column proof. Given:triangle TRS is congruent to triangle RTW Prove: RSTW is a parallelogram
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Answer 1

The triangles are congruent. That means the angles RWT and RST are equal.

We also know that WRT = RTS and SRT = WTR. For any one side (RW or WT or TS or RS) to be parallel to the opposite side, the two angles in between must equal 180 degrees. Because the angles in any triangle add up to 180 degrees, this is true. Therefore it is by definition a parallelogram.