new countdown second edition

2. • What is a line ?
• Which instrument in the geometry box has a
curved edge?
• How many lines can be drawn through a given
point?

3. Which angle is formed by the legs of
the chair?

4. Which type of shape is this?

5. TRIANGLES

6. In today class, we will learn about
 What is a triangle?
 Parts of triangle
 Types of triangle
1. Scalene triangle
a. Examples
2. Isosceles triangle
b. Examples
3. Equilateral triangle
c. Example
Objectives

7. Pg: 175
What is a triangle?
• The word triangle is a combination
of two words.
• Tri means “THREE “.
• Angulus means “ANGLES or CORNERS”

8. Definition
A triangle is a geometrical shape
which has three sides and three
angles

9. A
B C
BC

10. • In ΔABC,
1. Sides or edges:
mAB
mAC
mBC
2. Corners or vertices:
Three corners A, B, and C
3. Angles:
∠A, ∠B, ∠C
Parts of Triangle
m represents
measurements

12. C:UsersUSERDesktopTriangles -
Educational Video for Kids.mp4

13. Scalene Triangle
A scalene triangle has three
sides of unequal length
AND
three angles of different sizes.

15. Isosceles Triangle
At least two sides are the
same length
AND two angles are the
same size

17. Equilateral Triangle
An equilateral triangle
has three equal sides
AND
three equal angles in sizes.

19. Recapitulation
Sides / Edges
Parts of triangle Types of triangles
TRIANGLE
vertex
Angles Equilateral
Isosceles
Scalene

20. Any
Question???

22. Q1: What is a triangle?
Q2: How many types of
triangles? Name them.
Q3. Can a triangle have all equal
sides?

23. A
B C
6 cm
Q4: Which type of triangle it is?
Scalene triangle

24. Q5: Classify the given
below triangles.
Isosceles Equilateral

25. Home Work
Solve the question number 2 and 3 of
exercise 13a of your book.
Submission Date: 19 Dec, 2019