1. Parallelograms
Parallelogram - A quadrilateral with both pairs of opposite sides parallel.
Theorem 8.3
Opposite sides of a parallelogram are congruent.
Theorem 8.4
Opposite angles of a parallelogram are congruent.

2. Parallelograms Theorem 8.5
Consecutive angles in a parallelogram are supplementary.
Theorem 8.6
If a parallelogram has one right angle, it has four right angles.
Theorem 8.7
The diagonals of a parallelogram bisect each other.
Theorem 8.8
Each diagonal of a parallelogram separates the parallelogram into two congruent triangles.

3. ABCD is a parallelogram.
Answer:
Example 2-2d

4. A B C D
MULTIPLE-CHOICE TEST ITEM What are the coordinates of the intersection of the diagonals of parallelogram LMNO, with vertices L(0, –3), M(–2, 1), N(1, 5), O(3, 1)?
Answer: B
Example 2-3c