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This ppt includes the following topics:-

Classifying Triangles by Sides

Classifying Triangles by Angles

Parts of an Isosceles Triangle

Angle Sum Theorem

Third Angle Theorem

Corollaries

Classifying Triangles by Sides

Classifying Triangles by Angles

Parts of an Isosceles Triangle

Angle Sum Theorem

Third Angle Theorem

Corollaries

1.
Classifying Triangles &

Angles of Triangles

Sections 4-1 & 4-2

Angles of Triangles

Sections 4-1 & 4-2

2.
A triangle is the figure formed by 3

segments joining 3 noncollinear

points. Each of the 3 points is a

vertex. The segments are the sides.

Sides : AB, BC , CA A

Vertices : points A, B, C

C B

segments joining 3 noncollinear

points. Each of the 3 points is a

vertex. The segments are the sides.

Sides : AB, BC , CA A

Vertices : points A, B, C

C B

3.
Classifying Triangles by Sides

Scalene Triangle –

no sides congruent

Isosceles Triangle –

At least 2 sides congruen

Equilateral Triangle –

All sides congruent

Scalene Triangle –

no sides congruent

Isosceles Triangle –

At least 2 sides congruen

Equilateral Triangle –

All sides congruent

4.
Classifying Triangles by Angles

700

50 0

Acute – 3 acute angles

600

Right – 1 right angle

400

1200

200 Obtuse – one obtuse angle

600

600 600

Equiangular – all angles congruent

700

50 0

Acute – 3 acute angles

600

Right – 1 right angle

400

1200

200 Obtuse – one obtuse angle

600

600 600

Equiangular – all angles congruent

5.
Parts of an Isosceles Triangle

vertex angle

leg leg

base

base angles

vertex angle

leg leg

base

base angles

6.
Angle Sum Theorem

The sum of the measures of the

angles of a triangle is 180.

1000

40 0 400

The sum of the measures of the

angles of a triangle is 180.

1000

40 0 400

7.
Third Angle Theorem

If2 angles of one triangle are congruent to 2

angles of another triangle, then the third

angles are congruent.

If2 angles of one triangle are congruent to 2

angles of another triangle, then the third

angles are congruent.

8.
Corollaries

statements that can be easily proved using a theorem

Each angle of an equiangular triangle has

measure 60.

In a triangle, there an be at most one right

angle or obtuse angle.

The acute angles of a right triangle are

complementary.

statements that can be easily proved using a theorem

Each angle of an equiangular triangle has

measure 60.

In a triangle, there an be at most one right

angle or obtuse angle.

The acute angles of a right triangle are

complementary.

9.
Exterior Angle Theorem

The measure of an exterior angle of a

triangle equals the sum of the measures

of the 2 remote interior angles.

Remote interior

350 angles

Exterior 750 400

The measure of an exterior angle of a

triangle equals the sum of the measures

of the 2 remote interior angles.

Remote interior

350 angles

Exterior 750 400

10.
Joke Time

What has wings and solves number

problems?

A mothematician

What has wings and solves number

problems?

A mothematician

11.
What did one math book say to the

other math book?

Don’t bother me! I’ve got my own

problems!

other math book?

Don’t bother me! I’ve got my own

problems!

12.
What would a math student say to a

fat parrot?

fat parrot?