1. Quadrilaterals
Four sided polygons

2. Parallelograms
Definition- A quadrilateral with both pairs of opposite sides parallel.

3. Parallelograms-Theorems
8.3- Opposite sides are congruent
8.4- Opposite angles are congurent
8.5- Consecutive angles are supplementary

4. Theorems (con’t)
8.6-If a parallelogram has one right angle, it has four right angles.
8.7-The diagonals bisect each other.
8.8- Each diagonal separates the parallelogram into two congurent triangles.

5. Rectangles Definition- a quadrilateral with four right angles.
Properties-
1.Opposite sides are congruent and parallel
2.Opposite angles are congruent
3.Consecutive angles are supplementary
4.Diagonals are congruent and bisect each other
5.All four angles are right angles

6. Rectangles Theorems
8.13- If a parallelogram is a rectangle, then the diagonals are congruent.
8.14-If the diagonals of a parallelogram are congruent, then the parallelogram is a rectangle.

7. Rhombi
Definition- a quadrilateral with all four sides congruent.

8. Rhombi Theorems 8.15- The diagonals are perpendicular
8.16- If the diagonals of a parallelogram are perpendicular, then the parallelogram is a rhombus.
8.17- Each diagonal of a rhombus bisect a pair of opposite angles.

9. Rhombi Properties 1.It has all the same properties as a parallelogram
A. Opposite sides are congruent
B. Opposite angles are congruent
C. Consecutive angles are supplementary
D. The diagonals bisect each other
E. Each diagonal makes two congruent triangles

10. Properties (cont’) 2. All sides are congruent
3. Diagonals are perpendicular
4.Diagonals bisect the angles of the rhombus

11. Squares
Definition- a quadrilateral that is both a rhombus and a rectangle

12. Squares Properties 1. All the properties of a parallelogram
A. Opposite sides are congruent
B. Opposite angles are congruent
C. Consecutive angles are supplementary
D. The diagonals bisect each other
E. Each diagonal separates it into two congruent triangles

13. Properties (cont’) 2. All the properties of a rectangle
A. All four angles are right angles
B. the diagonals are congruent
3. All the properties of a rhombus
A. All sides are congruent
B. Diagonals are perpendicular
C. Diagonals bisect the angles of the square

14. Trapezoids
Definition- a quadrilateral with exactly one pair of parallel sides
Isosceles trapezoid- a trapezoid where the legs are congruent
Median- the segment that joins the midpoints of the legs of a trapezoid

16. Trapezoids-Theorems
8.18- Both pairs of base angles of an isosceles trapezoid are congruent
8.19- The diagonals of an isosceles trapezoid are congruent
8.20- The median of a trapezoid is parallel to the bases, and its measure is one-half the sum of the measures of the bases.
(median = ½(b1 + b2)