4. Bounded by three
or more sides
Line that
Straight Polygon joins two
line sides non-
meet at adjacent
point vertices of
called a Made of polygon is
vertex straight lines, called a
and the shape diagonal
is “closed”
5. Which of following are polygon? Why?
POLYGON because have straight sides and enclosed
NOT A POLYGON because not enclosed figure
NOT A POLYGON because has a curve
12. I have 3 straight sides.
I have 3 vertices.
What shape am I?
I’m a
triangle!
13. TRIANGLE
Equilateral Isosceles Triangle Scalene Triangle
Triangle
Three equal sides Two equal sides No equal sides
Three equal Two equal angles No equal angles
angles, always 60°
14.
15. I have 4 straight sides.
I have 4 vertices.
What shape am I?
I’m a
quadrilateral!
16. QUADRILATERAL
Quadrilateral just means "four sides" (quad means four, lateral means side).
Any four-sided shape is a Quadrilateral.
But the sides have to be straight, and it has to be 2-dimensional.
28. Symmetry
• An object is said to have line(s) of symmetry if
one side of it overlaps exactly with the other.
Line of symmetry
(vertical)
Line of symmetry
(diagonal)
Line of symmetry
(horizontal)
29. 1. Which of the following is a correct definition
of a polygon?
A . A closed plane figure with 3 or more straight edges as its sides.
B. A figure with 3 or more straight edges.
C. A closed figure with either straight or curved edges as its sides.
D. A plain figure with 3 or more straight edges as its sides.
30. 2. Name the polygon
A. Triangle
B. Quadriangle
C. Hexagon
D. Quadrilateral
