1. Students will name two dimensional figures (9-4).
Objective:
Students will name two dimensional figures (9-4).

2. Vocabulary Polygon – a simple closed figure with three or more sides.
Triangle – 3 sided polygon.
Quadrilateral – 4 sided polygon.
Pentagon – 5 sided polygon.
Hexagon – 6 sided polygon.
Octagon – 8 sided polygon.
Decagon – 10 sided polygon.

3. Vocabulary continued…
Regular polygon – a polygon with all sides congruent and all angles congruent.
Parallel – lines going in the same direction and always being the same distance apart. They never meet or cross each other.

4. Vocabulary continued…
Parallelogram – a quadrilateral that has both pairs of opposite sides equal and parallel.
Equilateral triangle – a triangle with 3 congruent sides.

5. Special Characteristics of certain quadrilaterals
square
All sides are congruent
All angles are right angles
Opposite sides are parallel.
parallelogram
Opposite sides are congruent
Opposite side are parallel

6. Special Characteristics of certain quadrilaterals
Opposite sides are congruent
All angles are right angles
Opposite sides are parallel
rectangle

7. Examples
Name each polygon. Then tell if the polygon is a regular polygon.

8. Examples
Name each polygon. Then tell if the polygon is a regular polygon.
This polygon is a pentagon.
The sides and angles are
congruent so it is a regular
polygon.

9. Examples
Name each polygon. Then tell if the polygon is a regular polygon.
The polygon is a triangle. The
sides and angles are not
congruent so it is not a regular
Polygon.

10. Examples
Name each polygon. Then tell if the polygon is a regular polygon.
The polygon is a quadrilateral.
The sides are not all congruent
So it is not a regular polygon.

11. Examples
Explain how a rectangle and a parallelogram are alike and how they are different.

12. Examples A rectangle and a parallelogram are alike because they:
have 4 sides
have opposites sides parallel
have opposite sides congruent.
They are different because a rectangle has 4 right angles and a parallelogram does not necessarily have 4 right angles.

13. Examples The traffic sign shown is a yield sign.
What shape is a yield sign?
What is the perimeter of the sign?
36 in.
YIELD
36 in.
36 in.

14. Examples The traffic sign shown is a yield sign.
What shape is a yield sign? It is shaped like an equilateral triangle.
What is the perimeter of the sign? The perimeter is the sum of the lengths of the sides = P = 108 in.
36 in.
YIELD
36 in.
36 in.

15. Guided Practice
Name each polygon. Then tell if the polygon is a regular polygon.

16. Guided Practice
Name each polygon. Then tell if the polygon is a regular polygon.
Hexagon: no
equilateral
triangle: yes

17. Guided Practice
Explain how each pair of figures is alike and each pair is different.

18. Guided Practice
Explain how each pair of figures is alike and each pair is different.
Alike: quadrilaterals, opposite sides parallel, 4 right angles,
opposite sides congruent.
Different: a square must have 4 congruent sides, a rectangle
may not have 4 congruent sides

19. Examples
Draw an example of each polygon. Mark any congruent sides, congruent angles, and right angles.
parallelogram

20. Examples
Draw an example of each polygon. Mark any congruent sides, congruent angles, and right angles.
parallelogram