When you say the word triangle, young children probably think of a closed shape with three different sides. Yet, there are many different kinds. When I was teaching fourth grade, I tried to do some fun activities to teach about the different types of triangles. Use these art projects, investigative activities and fun games to teach kids about classifying triangles.
Introducing the Types of Triangles
Before doing any of these activities, teachers should introduce their students to the types of triangles with basic definitions. These include:
- Equilateral: Triangles with three equal sides and angles (three 60 degree angles)
- Isosceles: Triangles with two equal sides and angles
- Scalene: Triangles without any equal sides or angles
You can also classify triangles based on their angles alone. Students should know that all three angles in a triangle must add up to 180 degrees. There are three different ways to classify triangles in this manner:
- Acute triangle: All three angles are less than 90 degrees, three acute angles.
- Right triangle: Has one right, 90 degree angle.
- Obtuse triangle: Has one angle bigger than 90 degrees, an obtuse angle.
For pictures and some interactive triangle activities go to mathisfun.com. It’s also a good idea to have a classifying triangle poster up on the wall for kids to look at while doing the following activities.
Once your kids understand the basics, you can have them make triangle families. For this art and math activity, you will need construction paper in different colors, rulers, scissors, glue, yarn, markers and googly eyes. One day, you can have students choose to make a family based on their sides and angles (equilateral, isosceles and scalene). First, using a ruler, students need to draw equilateral, isosceles and scalene triangles. After cutting out their triangles, students can create a triangle family with markers, yarn for hair and wiggly eyes. They can name their family members. For instance, some cute names are Papa Scalene or Baby Equilateral. They next day, they can continue their family with the acute, right and obtuse triangles.
Using six different colors, you can cut out yarn to make different types of triangles. For instance, using purple yarn, you should cut out three equal pieces of yarn to make an equilateral triangle. Then, choose another yarn color to make three different lengths of yarn for a scalene triangle…and so on. Students can glue the yarn into a triangle shape. For an extension,you can give them rulers and protractors so they can label the length of the sides and measure the angles.
Name that Triangle
Draw a triangle (and its classification) on a big name tag and stick it on each child’s back. Put children into pairs and have the children read clues to their partner about what triangle is on their back. For instance, “your triangle has three equal sides.” They should guess equilateral. Sometimes, triangles have more than one classification. For instance, there is such a thing as an isosceles right triangle. After students understand basic triangle classifications, these ideas can be explored on mathwarehouse.com.
Classifying triangles can be confusing but these activities can help students grasp the basics!
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