A polygon is any shape where all the sides are straight. Here are some examples of polygons:
However, the following shape is not a polygon, since it doesn't have all straight sides:
The corners of a polygon are called vertices, and the sides are called edges. For a polygon, the number of vertices always equals the number of edges.
Now, how many vertices does the polygon shown below have?
The vertices are the corners. The polygon has vertices in total, as shown below.
Which of the following is not a polygon?
A polygon is any shape where all the sides are straight.
The shape below has curved sides.
Therefore, III is not a polygon.
How many edges does the polygon shown below have?
Edges are straight line segments that connect the vertices of a polygon.
The polygon has edges in total, as shown below.
How many vertices does the polygon shown above have?
|
a
|
$7$ |
|
b
|
$6$ |
|
c
|
$4$ |
|
d
|
$3$ |
|
e
|
$5$ |
How many edges does the polygon shown above have?
|
a
|
$5$ |
|
b
|
$4$ |
|
c
|
$7$ |
|
d
|
$8$ |
|
e
|
$6$ |
Polygons with a specific number of sides, or vertices, have special names.
| Number of sides (or vertices) | Name | Shape |
|---|---|---|
| Triangle |
 |
|
| Quadrilateral |
 |
|
| Pentagon |
 |
|
| Hexagon |
 |
|
| Heptagon |
 |
|
| Octagon |
 |
|
| Nonagon |
 |
|
| Decagon |
 |
Only one of the following is a heptagon, but which? Let's find out.
A heptagon has vertices and straight sides. Therefore, the answer is III.
Notice that shape I is not a polygon since it has a curved side. Shape II has vertices, making it an octagon.
What is the name of the polygon shown below?
The polygon has vertices, as shown below.
The polygon also has straight sides connecting its vertices.
Therefore, it's a quadrilateral.
What is the name of the polygon shown above?
|
a
|
Quadrilateral |
|
b
|
Triangle |
|
c
|
Pentagon |
|
d
|
Hexagon |
|
e
|
Octagon |
What is the name of the polygon shown above?
|
a
|
Quadrilateral |
|
b
|
Pentagon |
|
c
|
Hexagon |
|
d
|
Heptagon |
|
e
|
Octagon |
Which of the following is a nonagon?
A nonagon has vertices and straight sides. Therefore, the answer is II.
Notice that shape I has vertices, and shape III is not a polygon since it has a curved side.
