1. triangles
Submitted to
Mrs. Jyoti Arora

2. TRIANGLES

3. Basic learning
A triangle has :
3 angles
3 sides
3 vertices
It has 4 congruence
The sum of its angles is
always 180

4. Different
triangles

5. Shapes of triangles
1. Scalene triangle :
its all sides are different in length .
2. Equilateral triangle :
its all sides are equal .
3. Isosceles triangle :
its any 2 sides are equal.

6. Types of triangle
Acute angled triangle :
less than 90°
Right angled triangle :
Equal to 90°
Obtuse angled triangle :
Bigger than 90°

7. Some ex. Of
triangles

8. Different congruencies of
triangle
• SSS ( side , side , side ) : in this congruent
form all the sides of triangle are equal .
• SAS ( side , angle , side ) : in this congruent
form 2 sides and 1 angle are equal .
• ASA ( angle , side , angle ) : in this congruent
form 2 angles and 1 side are equal .
• AAA ( angle , angle , angle ) : in this
congruent form all 3 angles are equal

9. AREA OF TRIANGLE
• Formula :
½ base x height
heron formula :
√s ( s – a ) ( s – b ) ( s – c )

10. The end
By
Sakshi Bhardwaj
IX B