1. 6.2 Properties of Parallelograms
Boyd/Usilton

2. Properties of Parallelograms
A parallelogram is a quadrilateral with both pairs of opposite sides parallel.

3. Theorem 6-3
If a quadrilateral is a parallelogram, then its opposite sides are congruent.
If ABCD is a Then AB = CD and BC = DA

4. Theorem 6-4
If a quadrilateral is a parallelogram, then its consecutive angles are supplementary.
If ABCD is a Then m<A + m<B = 180 m<B + m<C = 180 m<C + m<D = 180 m<D + m<A = 180

5. Theorem 6-5
If a quadrilateral is a parallelogram, then its opposite sides are congruent.
If ABCD is a Then <A = <C and <B = <D

6. Theorem 6-6
If a quadrilateral is a parallelogram, then its diagonals bisect each other.
If ABCD is a Then AE = CE and BE = DE

7. Theorem 6-7
If three or more parallel lines cut off congruent segments on one transversal, then they cut off congruent segments on every transversal.
If AB ll CD ll EF and AC = CE Then BD = DF