introduction to triangles, class V, based on DAV Books

1. Triangles
Class V
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2. I can be big or small.
You can find me all around.
I am made up of three
connected lines.
I have three vertices
I have three angles
Who am I?
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3. 3

4. I am a Triangle
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5. Parts of Triangle
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6. Worksheet 1 from DAV Book
to be done.
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7. Note that
• the unit of measure of an angle is called DEGREE.
Recall
• Angle on a straight line is a straight angle and it
measures 1800 .
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8. Angle Sum Property of Triangle
Property: Sum of the three angles of a triangle
is always 1800
To be done by activity method in class room
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9. Worksheet 2 from DAV Book
to be done.
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10. Side inequality Property of
Triangle
To be done by activity method in class room
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11. Lets take an example where the sides are
given to be 10 cm, 4 cm and 3 cm. check if it
is possible to make a triangle with given sides
or not.
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12. Worksheet 3 from DAV Book
to be done.
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13. Types of Triangle
On the basis of sides On the basis of angles
• Scalene triangle
• Isosceles triangle
• Equilateral triangle
• Acute angled triangle
• Right angled triangle
• Obtuse angled triangle
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14. Types of Triangle on the
basis of sides
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15. Scalene Triangle
A triangle in which length of all three sides is
different is called a scalene triangle
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16. Isosceles Triangle
A triangle in which length of any two sides is same
is called an isosceles triangle
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17. Equilateral Triangle
A triangle in which length of all three sides is same
is called an equilateral triangle
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18. Types of Triangle on the
basis of angles
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19. Acute angled Triangle
A triangle in which all three angles are acute ( <900)
is called acute angled triangle.
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20. Right angled Triangle
A triangle in which one angle is right ( = 900) is
called right angled triangle.
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21. Obtuse angled Triangle
A triangle in which exactly one angle is obtuse ( > 900)
is called obtuse angled triangle.
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22. Worksheet 4 from DAV Book
to be done.
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23. Thanks!!!
Prepared by: Richa Bhardwaj
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