Polygons for grade 7.pdf We are MATHLETHES

Math for a better life and greater knowledge. Math is a very great subject in our school that can help you understand about statistics and many more about mathematics.

1. Polygon
s

2. Definitions:
•
Polygon
—
closed
plane figure
bounded by three or
more segments (sides) that meet only at their
endpoints (vertices), so that each endpoint (vertex)
is contained by exactly two segments (sides)
•
Vertex
–
each endpoint of a side. Plural is
vertices
.
You can name a polygon by listing its vertices
consecutively
. For instance,
PQRST
and
QPTSR

are two correct names for the polygon above.
VERTEX
VERTEX
Q
R
S
T
P
SIDE

3. Identifying Polygons
NO
NO
NO
YES

4. Classification of Polygons
•
Convex Polygon
•
Concave Polygon

5. •
Convex if no
diagonal is
in the exterior of the
polygon
•
Concave if a line does
contain a side of the
polygon containing a point
on the interior of the
polygon.
is a segment joining
non-consecutive vertices

6. Convex or concave?
•
Identify the polygon
and state whether it is
convex or concave.

7. Convex or Concave?
Convex
Convex
Convex
Concave
Concave

8. Types of Polygon
A polygon is
EQUILATERAL
If all of its sides are congruent.
A polygon is
EQUIANGULAR
if all of its interior angles are congruent.
A polygon is
REGULAR
if it is
equilateral and equiangular.

9. Polygons are named by the number
of sides they have
Heptagon
7
Hexagon
6
Pentagon
5
Quadrilateral
4
Triangle
3
Type of Polygon
Number of sides

10. Polygons are named by the number
of sides they have
n-gon
n
Type of Polygon
Number of sides
Dodecagon
12
Decagon
10
Nonagon
9
Octagon
8
11
Undecagon