1. 6.4 Properties of Rhombuses, Rectangles, and Squares A rhombus is a parallelogram with four congruent sides. A rectangle is a parallelogram with four right angles. A square is a parallelogram with four congruent sides and four right angles.

2. Special Parallelograms

3. Theorem 6.13 If a parallelogram is a rhombus, then its diagonals are perpendicular.

4. Theorem 6.14 If a parallelogram is a rhombus, then each diagonal bisects a pair of opposite angles.

5. Finding Angle Measures What are the measures of the numbered angles in rhombus ABCD?

6. Theorem 6.15 If a parallelogram is a rectangle, then its diagonals are congruent.

7. Finding Diagonal Length In rectangle RSBF, SF = 2x + 15 and RB = 5x – 12. What is the length of a diagonal? SF = RB 2x + 15 = 5x – 12 27 = 3x x = 9 SF = 2x + 15 SF = 2(9) + 15 SF = 18 + 15 SF = 33

8. More Practice!!!!! Homework – Textbook p. 379 – 380 # 1 – 39 ALL.