1. Special Quadrilaterals
Section 6.6:
Special Quadrilaterals

2. Proving Quadrilaterals are Rhombuses
You have learned three ways to prove that a quadrilateral is a rhombus. 1) You can use the definition and show that a quadrilateral is a parallelogram that has four congruent sides. It is easier, however, to use the Rhombus Corollary and simply show that all four sides of the quadrilateral are congruent.

3. Show that the quadrilateral is a parallelogram and that the diagonals are perpendicular (Theorem 6.11).
3) Show that the quadrilateral is a parallelogram and that each diagonal bisects a pair of opposite angles (Theorem 6.12).

4. Example 1: Copy the chart
Example 1: Copy the chart. Put an X in the box if the shape always has the given property.
Property
Parallel-
ogram
Rectangle
Rhombus
Square
Kite
Trapezoid
Both pairs of opp. sides are ||.
Exactly 1 pair of opp. sides are ||.
Diagonals are perpendicular.
Diagonals are congruent.
Diagonals bisect each other.

5. Example 2: Copy the chart
Example 2: Copy the chart. Put an X in the box if the shape always has the given property.
Property
Parallel-
ogram
Rectangle
Rhombus
Square
Kite
Trapezoid
Both pairs of opp. sides are congruent.
Exactly 1 pair of opp. sides are congruent.
All sides are congruent.
Both pairs of opp. angles are congruent.
Exactly 1 pair of opp. angles are congruent.
All angles are congruent.

6. In-class Assignment
pg. 367 – 368; 14 – 18

7. HOMEWORK
pg. 814; 25 – 30, 35 – 41