Objective:
Illustrate polygons:
convexity
angles
sides
“Take a look”
1. How many sides are there in the figure? Three
2. What shape is represented by the figure? Triangle
1. How many sides are there in the figure? Four
2. What shape is represented by the figure? Square
1. How many sides are there in the figure? Four
2. What shape is represented by the figure? Rectangle
SQUARE
TRIANGLE
RECTANGLE
Polygons in Everyday Life
Polygons
are closed
figures made up
of three or more
line segments
joined at their
endpoints.
line segments
Polygons are classified as convex or non convex. A
polygon is convex if all segments joining any two points
of the polygon lie completely inside the polygon. On the
other hand, the polygon is concave if any two points of
the polygon lie outside the polygon.
Activity: Let’s React
Love - Convex
Like - Concave
Convex
Concave
Convex
Concave
Polygons are classified as convex or non convex. A
polygon is convex if all segments joining any two points
of the polygon lie completely inside the polygon. On the
other hand, the polygon is concave if any two points of
the polygon lie outside the polygon.
sides
Parts of
a
Polygon
angle
vertex
A polygon is a union of non-collinear
segments, the sides, on a plane that
meet at their endpoints, the vertices, so
that each endpoint (vertex) is contained
by exactly two segments(sides). The
angles on the inside of a polygon formed
by each pair of adjacent sides.
P
o
l
y
g
o
n
side
p
a
r
t
s
side
angle
side
side
Activity : Let’s Count
3 sides
3 angles
6 sides
6 angles
8 sides
8 angles
Polygons are
classified
according to
the number
of sides.
Common
names for
polygons are
listed in the
table.
QUIZ
A. Use polygon ABCDE at the
right to answer the following
questions.
1. What are the vertices, angles,
and sides of the polygon?
2. Classify the polygon by the
number of sides.
3. Is the polygon convex or
concave?
B. Illustrate the following;
4. A heptagon
5. A convex polygon