Transcript 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. •

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.
Special Parallelograms
Theorem 6.13
• If a parallelogram is a rhombus, then its
diagonals are perpendicular.
Theorem 6.14
• If a parallelogram is a rhombus, then each
diagonal bisects a pair of opposite angles.
Finding Angle Measures
• What are the measures of the numbered angles in
rhombus ABCD?
m1  90
m2  58
m3  58
m1  m3  m4  180
90  58  m4  180
148  m4  180
m4  32
Theorem 6.15
• If a parallelogram is a rectangle, then its
diagonals are congruent.
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
More Practice!!!!!
• Homework – Textbook p. 379 – 380 # 1 –
39 ALL.