Classifying Triangles and Missing Angles

Classifying Triangles

Essential Question:

How can I classify triangles?

Student Objectives:

• I can classify triangles by its angles.

• I can classify triangles by its sides.

Multiple Choice

Quick Review:

The sum of all the angles in a triangle is:

• 90 degrees

• 360 degrees

• 180 degrees

Fill in the Blanks

The angles for this triangle are 100 degrees and 55 degrees. What is the measurement of the missing angle?

Open Ended

A triangle is classified as an acute triangle if it...

Fill in the Blanks

In order to be classified as a right triangle, one of the angles must be

Poll

Is it possible for a triangle to have 2 right angles?

• yes

• no

• I don't know

Multiple Choice

Dania measured all the angles of a triangle and these are its angle measurement: 30 degrees, 130 degrees, and 20 degrees.

What type of triangle does she have?

• acute triangle

• right triangle

• obtuse triangle

Multiple Choice

Alex measured all the angles in a triangle. The angles are 60 degrees, 60 degrees, 60 degrees.

The triangle is classified as a ....

• right triangle

• acute triangle

• obtuse triangle

Equilateral

What does equilateral mean?

Multiple Select

Which of the following are the side lengths of an equilateral triangle?

• 3 in, 5in, 10in

• 5in, 5in, 5in

• 10in, 10in, 7in

Multiple Select

Kaniyah has an isosceles triangle, one of the side lengths is 7 inches. What are the other two side lengths?

• 4in

• 5in

• 6in

• 4in

Math Antics Video

Multiple Choice

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What is the name of this kind of triangle?

• Right
• Scalene
• Isosceles
• Equilateral

Multiple Choice

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What is the name of this kind of triangle?

• Right
• Isosceles
• Scalene
• Equilateral

Multiple Choice

How many acute angles must an acute triangle have?

• 2
• 1
• 4
• 3

Multiple Select

Triangles can be classified by what two things?

• Side length and angle measure

• Number of Vertices and number of sides

• Angle color and side height

• Number of points and number of lines

Multiple Select

Triangles can be classified by what two things?

• Side length and angle measure

• Number of Vertices and number of sides

• Angle color and side height

• Number of points and number of lines

Great Job Mathematicians!

Go on to Prodigy