CP - Lesson: Classifying Triangles

Classify Triangles

Objective: Classify triangles by their sides and angles.

Math Response

Given: all the angles in a triangle add up to 180 degrees.

If a triangle has one angle that measures 81 degrees and another that measures 47 degrees, what is the measure of the third angle?

Type answer here

Correct Answer: 52

Deg^°

Rad

Classify by ANGLES

Acute Triangle: ALL angles are less than 90 degrees.

​

Right Triangle: ONE angle is 90 degrees.

​

Obtuse Triangle: ONE angle is more than 90 degrees (and less that 180 degrees)

Dropdown

An obtuse triangle has

Select answer

obtuse angle(s).

Multiple Choice

Given: all the angles in a triangle add up to 180 degrees.

Classify the triangle that has one angle that measures 56 degrees and a second that measures 33 degrees.

• Acute triangle

• Right Triangle

• Obtuse Triangle

Dropdown

A right triangle has one angle that measures ​

Select answer

.

Classify by Sides

Scalene Triangles: NO sides are equal in length.

​

​

Sometimes they are labeled, sometimes they have the notches.

Classify by Sides

Equilateral Triangles: ALL sides are equal in length.

​

Sometimes they are labeled, sometimes they have the notches.

​

They are also called Equiangular Triangles.

Math Response

Given: All the angles in an Equilateral Triangle are equal.

What is the measure of ∠S?

Type answer here

Correct Answer: 60

Deg^°

Rad

Classify by Sides

Isosceles Triangles: TWO sides are equal in length.

​

Sometimes they are labeled, sometimes they have the notches.

Classifying Triangles

Now we are going to answer some questions about classifying triangles.

​

We will describe them as...

​

Acute, Right or Obtuse

​

AND

​

Scalene or Isosceles

​

Equilateral is an answer by itself. You wouldn't say Acute Equilateral

Drag and Drop

The triangle would be classified as a(n) ​

Placeholder

​

Placeholder

.

Drag these tiles and drop them in the correct blank above

obtuse

scalene

acute

right

isosceles

equilateral

Drag and Drop

The triangle would be classified as a(n) ​

Placeholder

​

Placeholder

Drag these tiles and drop them in the correct blank above

right

isosceles

acute

obtuse

scalene

equilateral