The document covers the properties of regular and irregular polygons, aiming to help learners define polygons and classify them based on their sides. It describes polygons as closed figures with a minimum of three sides and lists examples including triangles and decagons. Additionally, it distinguishes between regular and irregular polygons, providing definitions and characteristics for each type.

1. PROPERTIES OF
REGULAR AND
IRREGULAR POLYGONS
DAY 1 WEEK 1

2. Learning Objectives:
At the end of the lesson, the learners will
be able to:
1. Define a polygon.
2. Classify polygon according to its sides and
as regular or irregular.

3. Properties of Regular and Irregular Polygons
Round 1: Naming Polygons
Players have 10 seconds to write down the name
of the polygon based on the number of sides and
what polygon it reminds you. Correct answers
earn 1 point.
Round 2: Players have 10 seconds to write down
the number of sides. Correct answers earn 1
point.

10. WHAT ARE POLYGONS?
 A Polygon is a closed figure made up of line
segments (not curves) in a two-dimensional
plane. Polygon is the combination of two
words, i.e. poly (means many) and gon (means
sides).
 A minimum of three-line segments is required
to connect end to end, to make a closed
figure. Thus, a polygon with a minimum of
three sides is known as Triangle and it is
also called 3-gon. An n-sided polygon is
called n-gon.

12. EXAMPLES OF POLYGONS
• Three-sided polygons - triangles
• Four-sided polygons - quadrilaterals
• Five-sided polygons - pentagons
• Six-sided polygons - hexagons
• Seven-sided polygons - heptagons*
• Eight-sided polygons - octagons
• Nine-sided polygons - nonagons*
• Ten-sided polygons - decagons*
• Eleven-sided polygons - hendecagons*
• Twelve-sided polygons - dodecagons*

13. CLASSIFICATIONS OF POLYGONS
A. Equilateral polygon is a polygon
whose sides are all congruent.

14. CLASSIFICATIONS OF POLYGONS
B. Equiangular polygon is a polygon
whose all angles are congruent.

15. CLASSIFICATIONS OF POLYGONS
C. Regular polygon is a polygon that
is both equilateral and equiangular.

16. CLASSIFICATIONS OF POLYGONS
D. Irregular polygon is a polygon whose
sides and angles are not equal.

17. CLASSIFICATIONS OF POLYGONS
D. Irregular polygon is a polygon whose
sides and angles are not equal.

18. A scalene triangle is considered
an irregular polygon, as the
three sides are not of equal
length and all the three internal
angles are also not in equal
measure and the sum is equal to
180°. In the triangle PQR, the
sides PQ, QR, and RP are not
equal to each other i.e. PQ ≠ QR
≠ RP. Also, angles ∠P, ∠Q, and
∠R, are not equal, ∠P ≠ ∠Q ≠
∠R.

19. A rectangle is considered an
irregular polygon since only
its opposite sides are equal in
equal and all the internal
angles are equal to 90°. In
the given rectangle ABCD,
the sides AB and CD are
equal, and BC and AD are
equal, AB = CD & BC = AD.
And, ∠A = ∠B = ∠C = ∠D =
90 degrees.

20. Which figure is a polygon?

21. 1 2 3
4 5 6

22. 7
8
9 10