Proofs Quadrilaterals

Fill in the missing reason for the proof.

• Opposite angles are congruent.

• Alternate interior angles formed by parallel lines are congruent.

• Vertical angles are congruent.

• CPCTC

Choose the correct missing reasons for the proof.

• 4) CPCTC; 6)All quads are parallelograms

• 4) Alternate Interior Angles are congruent; 6) Definition of paralelogram

• 4)CPCTC; 6)Definition of parallelogram

• 4) Alternate Interior Angles are congruent; 6) All quads are parallelograms

The missing reason is the same for steps 2 and 4. What is the missing reason?

• If alternate interior angles are congruent, then the lines are parallel.

• If vertical angles are congruent, then the lines are parallel.

• Definition of parallelogram

• Alternate interior angles formed by parallel lines are congruent.

Fill in the missing reason for the proof.

• If alternate interior angles are congruent, then the lines are parallel.

• Definition of parallelogram

• Definition of parallel lines

• Opposite sides of a parallelogram are congruent.

Which theorem can be used to prove the quadrilateral is a parallelogram?

• Parallelogram Opposite Sides Converse Theorem

• Parallelogram Opposite Angles Converse Theorem

• Opposite Sides Parallel and Congruent Theorem

• Parallelogram Diagonals Converse Theorem

Which theorem can be used to prove the quadrilateral is a parallelogram?

• Parallelogram Opposite Sides Converse Theorem

• Parallelogram Opposite Angles Converse Theorem

• Opposite Sides Parallel and Congruent Theorem

• Parallelogram Diagonals Converse Theorem

Is this enough information to prove this quadrilateral is a parallelogram?

• Yes, if two pairs of consecutive sides are congruent, then it is a parallelogram.

• No, there is not enough information.

Which theorem can be used to prove the quadrilateral is a parallelogram?

• Parallelogram Opposite Sides Converse Theorem

• Parallelogram Opposite Angles Converse Theorem

• Opposite Sides Parallel and Congruent Theorem

• Parallelogram Diagonals Converse Theorem

What is reason #3? Make sure you write-in the reasons on your proofs.

• Definition of a parallelogram

• Definition of a quadrilateral

• opposite sides are congruent property

• opposite sides are supplementary

Which theorem can be used to prove the quadrilateral is a parallelogram?

• Parallelogram Opposite Sides Converse Theorem

• Parallelogram Opposite Angles Converse Theorem

• Opposite Sides Parallel and Congruent Theorem

• Parallelogram Diagonals Converse Theorem