A polygon is made of all line segments, closed with

no gaps.  The smallest possible number of sides is

three and names a triangle.  Triangles are named

one of two ways by their sides or by their angles.

According to their sides triangles can be either

all sides matching, equilateral

at least two sides matching, isosceles

or no sides matching, scalene

What is a triangle with no sides matching called?

Classifying triangles by their sides one with  

all sides matching is equilateral,

at least two sides matching is isosceles,

no sides matching is called scalene

What is a triangle with at least two sides matching

called?

Classifying triangles by their sides one with  

all sides matching is equilateral,

at least two sides matching is isosceles,

no sides matching is called scalene

What is a triangle with all sides matching

called?

Classifying triangles by their angles, look at the largest

angle.  The largest angle names the triangle.  

If the largest angle is less than 90 degrees, the triangle

is called an acute triangle according to its angles.

If the largest angle is 90 degrees, the triangle is called a

right triangle according to its angles.

If the largest angles is more than 90 degrees, the

triangle is called an obtuse triangle.

What is a triangle with a right angle called?

a(n)                        triangle

Classifying triangles by their angles, look at the largest

angle.  The largest angle names the triangle.  

If the largest angle is less than 90 degrees, the triangle

is called an acute triangle according to its angles.

If the largest angle is 90 degrees, the triangle is called a

right triangle according to its angles.

If the largest angles is more than 90 degrees, the

triangle is called an obtuse triangle.

What is a triangle with all angles less than 90 degrees 

called?          a(n)                     triangle

Matching markings indicate congruent (matching) sides.

An ∟ indicates a right angle.

Classifying triangles by their angles, look at the largest

angle.  The largest angles names the triangle.  

If the largest angle is less than 90 degrees, the triangle

is called an acute triangle according to its angles.

If the largest angle is 90 degrees, the triangle is called a

right triangle according to its angles.

If the largest angles is more than 90 degrees, the

triangle is called an obtuse triangle.

What is a triangle with one angle more than 90 degrees

called?          a(n)                     triangle