TrianglesClass V

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I can be big or small.You can find me all around.I am made up of three

connected lines.I have three verticesI have three angles

Who am I?

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I am a Triangle

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Parts of Triangle

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Worksheet 1 from DAV Book

to be done.

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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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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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Worksheet 2 from DAV Book

to be done.

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Side inequality Property of

Triangle

To be done by activity method in class room

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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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Worksheet 3 from DAV Book

to be done.

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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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Types of Triangle on the

basis of sides

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Scalene Triangle

A triangle in which length of all three sides is

different is called a scalene triangle

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Isosceles Triangle

A triangle in which length of any two sides is same

is called an isosceles triangle

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Equilateral Triangle

A triangle in which length of all three sides is same

is called an equilateral triangle

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Types of Triangle on the

basis of angles

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Acute angled Triangle

A triangle in which all three angles are acute ( <900) is called acute angled triangle.

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Right angled Triangle

A triangle in which one angle is right ( = 900) is called right angled triangle.

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Obtuse angled Triangle

A triangle in which exactly one angle is obtuse ( > 900) is called obtuse angled triangle.

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Worksheet 4 from DAV Book

to be done.

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Thanks!!!

Prepared by: Richa Bhardwaj

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