geometry section 1-6 1112

Section 1-6Two-Dimensional Figures

Monday, September 22, 14

Essential Questions

• How do you identify and name polygons?

• How do you find perimeter, circumference, and area of two-dimensional figures?


Vocabulary1. Polygon:

2. Vertex of a Polygon:

3. Concave:

4. Convex:

5. n-gon:

6. Equilateral Polygon:


Vocabulary1. Polygon: A closed figure whose sides are all line

segments

2. Vertex of a Polygon:

3. Concave:

4. Convex:

5. n-gon:




segments

2. Vertex of a Polygon: The point where two sides of a polygon meet

3. Concave:

4. Convex:

5. n-gon:




segments


3. Concave: A polygon that has an indentation

4. Convex:

5. n-gon:




segments



4. Convex: A polygon that has no indentations

5. n-gon:




segments




5. n-gon: A polygon that has n sides




segments




5. n-gon: A polygon that has n sides

6. Equilateral Polygon: A polygon where all sides are congruent


Vocabulary7. Equiangular Polygon:

8. Regular Polygon:

9. Perimeter:

10. Circumference:

11. Area:


Vocabulary7. Equiangular Polygon: A polygon where all angles

are congruent

8. Regular Polygon:

9. Perimeter:

10. Circumference:

11. Area:



are congruent

8. Regular Polygon: A polygon where all sides are congruent and all angles are congruent

9. Perimeter:

10. Circumference:

11. Area:



are congruent


9. Perimeter: The sum of the lengths of the sides of a polygon; The distance around a polygon

10. Circumference:

11. Area:



are congruent



10. Circumference:The distance around a circle

11. Area:



are congruent




C = 2π r = πd

11. Area:



are congruent




C = 2π r = πd

11. Area: The space in square units a figure covers


Area Formulas

Where are some places that you find these formulas?


Example 1Make four drawings (using a straight edge) so that two of your drawings are polygons and

two are not. Label which is which.

Polygons Not Polygons


Polygon Names3 sides: 4 sides: 5 sides:

6 sides: 7 sides: 8 sides:




Triangle




Triangle Quadrilateral




Triangle Quadrilateral Pentagon





Hexagon





Hexagon Heptagon





Hexagon Heptagon Octagon


Polygon Names



Polygon Names

9 sides: 10 sides: 12 sides:Nonagon


Polygon Names

9 sides: 10 sides: 12 sides:Nonagon Decagon


Polygon Names

9 sides: 10 sides: 12 sides:Nonagon Decagon Dodecagon


Example 2Draw a concave hexagon. Then draw a convex octagon.


Example 3Draw a regular quadrilateral.


Example 4Identify the figure based on the number of

sides. Is it concave or convex? Is it equilateral, equiangular, or neither?




Decagon




Decagon

Equilateral, but not equiangular




Decagon

Equilateral, but not equiangular

Concave


Example 5Find the perimeter of a rectangle whose length

is 8.3 cm and width is 3.2 cm.




8.3 cm




8.3 cm

3.2 cm




8.3 cm

3.2 cmP = 2l + 2w




8.3 cm

3.2 cmP = 2l + 2w

= 2(8.3) + 2(3.2)




8.3 cm

3.2 cmP = 2l + 2w

= 2(8.3) + 2(3.2)

= 16.6 + 6.4




8.3 cm

3.2 cmP = 2l + 2w

= 2(8.3) + 2(3.2)

= 16.6 + 6.4

= 23




8.3 cm

3.2 cmP = 2l + 2w

= 2(8.3) + 2(3.2)

= 16.6 + 6.4

= 23 cm


Example 6Find the circumference of a circle with a

diameter of 14 in.



diameter of 14 in.

14 in.



diameter of 14 in.

14 in. C = 2π r = πd



diameter of 14 in.

14 in. C = 2π r = πd

C = πd



diameter of 14 in.

14 in. C = 2π r = πd

C = πd

C = π(14)



diameter of 14 in.

14 in. C = 2π r = πd

C = πd

C = π(14)

C ≈ 43.98 in.


Problem Set


Problem Set

p. 61 #1-27 odd, 44-47

“Nobody got anywhere in the world by simply being content.” - Louis L’Amour


geometry section 1-6 1112

Education

pol y g o n

equilateral polygon

regular polygon

polygon names3 sides

equiangular polygon

n sides6

sides ofa polygon meet3

ver t e x o f