### Home > CCG > Chapter Ch7 > Lesson 7.2.5 > Problem 7-100

What else can you prove about parallelograms? Prove that if a pair of opposite sides of a quadrilateral are congruent and parallel, then the quadrilateral must be a parallelogram. For example, for the quadrilateral

Be sure to supply the reasoning for each step.

If a pair of opposite sides is parallel and congruent then the quadrilateral is a parallelogram.

Use the if part of the statement as the givens, and the then part of the statement as the prove portion in the proof.

This flowchart has 8 bubbles. Bubble # 1 has an arrow, pointing down to bubble # 4. Bubble numbers 2, 3, and 4 have arrows, pointing down to bubble # 5. Bubble #5 has an arrow, pointing down to bubble #6. Bubble # 6 has an arrow, pointing down to bubble # 7. Bubble 7 has an arrow, pointing down to bubble # 8.

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Bubble # 2 | Bubble # 3 | Bubble # 4 |

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Bubble # 8 |