1. Solutions to Check point 8.1
# #8
Sum of interior ’s = (n-2)  180
720 = (n-2)  180
Sum of interior ’s = (n-2)  180
Sum of interior ’s = (14 -2)  180
Sum of interior ’s = (12)  180
Sum of interior ’s = 2160
4 = n – 2
6 = n (Hexagon)
P 510
# #14
Sum of interior ’s = 360°
x = 360
249 + x = 360
x = 111
Sum = (n-2)  180
Sum = (6-2)  180
Sum = 720
x + 90 =720
x =150

2. Homework Questions?

3. Check Point
P. 521
# #6
P. 526
# #20
WARM UP (If you finish early)
Brainstorm and list all the differences and similarities between a square and a rectangle.

4. Geometry Section 8.4 - Properties of Rhombuses, Rectangles, and Squares
 I can use the properties of quadrilaterals to give a specific name to a drawing.
 I can use the properties of quadrilaterals to set up and solve equations to find variables.

6. iff
4 
iff
iff

7. Venn Diagram

8. EXAMPLE 1
Use properties of special quadrilaterals
EXAMPLE I
For any rhombus QRST, decide whether the statement is always or sometimes true. Draw a sketch and explain your reasoning. a. Q S b.
SOLUTION

9. EXAMPLE 1
Use properties of special quadrilaterals
For any rhombus QRST, decide whether the statement is always or sometimes true. Draw a sketch and explain your reasoning. Q R b.
SOLUTION
b. If rhombus QRST is a square, then all four angles are congruent right angles. So, If QRST is a square. Because not all rhombuses are also squares, the statement is sometimes true. Q R

10. EXAMPLE 2
Classify special quadrilaterals
Classify the special quadrilateral. Then find the values of x and y.
SOLUTION

11. iff
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iff
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12. EXAMPLE 3
List properties of special parallelograms
Sketch rectangle ABCD. List everything that you know about it.
• The figure is a parallelogram.
• The figure has 4 right angles.
• The diagonals of ABCD are 
Because ABCD is a parallelogram, it also has these properties:
• Opposite sides are parallel and .
• Opposite ’s are . Consecutive ’s are supplementary.
• Diagonals bisect each other.