Objective:

1. 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 • All sides are congruent • All angles are right angles • Opposite sides are parallel. square 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 36 in. The traffic sign shown is a yield sign. • What shape is a yield sign? • What is the perimeter of the sign? YIELD 36 in. 36 in.

14. Examples 36 in. 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. 36 + 36 + 36 = 108 P = 108 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