1
What is a polygon?
a closed figure made by joining line segmentsEach line segment intersects exactly two others.line segments do not intersect
*All images are either original artwork or are used with permission from Microsoft Word and Microsoft Online Design Gallery.
2
Are these figures polygons?
yes
yes
no
no
3
What is a regular polygon?
A regular polygon is a polygon whose sides are all the same length and whose angles are all the same.
4
These are not examples of regular polygons.
The sides are not all the same length.
The angles are not all the same.
5
Let’s look at some different kinds of polygons.
triangle What is a three-sided polygon?
6
Polygons
parallelogram What is a four-sided figure whose opposite sides are parallel?
7
Polygons
rectangle What is a four-sided polygon whose sides and angles are all the same?
8
Polygons
square What is a parallelogram or rectangle with four equal sides and angles?
9
Polygons
rhombus What is a parallelogram whose sides are all the same length?
10
Polygons
trapezoid What is a four-sided polygon having exactly one pair of parallel lines?
11
Polygons
pentagon What is a five-sided polygon?
12
Polygons
hexagon What is a six-sided pentagon?
13
Polygons
heptagon What is a seven-sided pentagon?
14
Polygons
octagon What is an eight-sided pentagon?
15
Let’s review the polygons we‘ve learned about today.regular polygon
triangleparallelogramrectanglesquarerhombus
trapezoidpentagonhexagonheptagonoctagon
16
Can you identify these polygons?
Match these.
Triangle eight sides
Heptagon three sides
Octagon seven sides
Match some more. Pentagon four sides
Hexagon five sides
Square six sides
19
Using your geoboards or dot paper, replicate these polygons.