line of symmetry

scalene

isosceles

acute-angled

congruent

right-angled

equilateral obtuse-angled

vertex

polygon

A triangle...

• is a closed figure (polygon)

• has three sides• has three

vertexes• has three interior

angles

vertexes

angle

side

Classifying Triangles

triangle

first name middle name last name

Which angle is the largest?

A

B

C

Which angle is the largest?

A

BC

Which angle is the largest?

B

A

C

obtuse-angled

acute-angled

right-angled

Possible Middle Names for Triangles

Classifying Triangles

acute-angledor

obtuse-angled or

right-angled

triangle

first name middle name last name

Equilateral Triangles

• 3 congruent sides• 3 congruent angles• 3 lines of symmetry

Isosceles Triangle

• 2 congruent sides• 2 congruent

angles• 1 line of

symmetry

Scalene Triangles

• 0 congruent sides• 0 congruent angles• 0 lines of symmetry

Classifying Triangles

equilateralor

isoscelesor

scalene

acute-angledor

obtuse-angled or

right-angled

triangle

first name middle name last name

Give the first, middle and last name for the following triangle:

first name middle name last name

isosceles

isosceles

Right-angledRight-angled

triangletriangle

Give the first, middle and last name for the following triangle:

first name middle name last name

triangletriangleobtuse-angled

obtuse-angled

isosceles

isosceles

Give the first, middle and last name for the following triangle:

first name middle name last name

triangletriangleacute-angledacute-angled

equilateral

equilateral

Give the first, middle and last name for the following triangle:

first name middle name last name

triangletriangleacute-angledacute-angled

scalenescalene

Give the first, middle and last name for the following triangle:

first name middle name last name

triangletriangleRight-angledRight-angled

scalenescalene

Recap: Classifying Triangles

equilateralor

isoscelesor

scalene

acute-angledor

obtuse-angled or

right-angled

triangle

first name middle name last name

Give the first, middle and last name for the following triangle:

first name middle name last name

What is the

measure of < A and

< B

A

B

Name The Angle

first name middle name last name

What is the measure of < A and < B

A

B 400

Name The Angle:

first name middle name last name

What is the

measure of < A and

< BA

300 B

Give the first, middle and last name for the following triangle:

first name middle name last name

What is the

measure of < A

A

300

Name The Angle

first name middle name last name

What is the

measure of < A , < B , and <

C

A

B C

What Can You Tell Me About These Figures?

What Can You Tell Me About This Figure?

What Can You Tell Me About This Figure?

What Can You Tell Me About This Figure?

What Can You Tell Me About This Figure?

What Can You Tell Me About This Figure?

Are These Figures Congruent?