Now that we have seen several examples of triangles, it’s time to create your own. For this activity you will be working with one partner in your group. You will receive a bag of pipe cleaners; there will be three different colours and those different colours represent different lengths. You can use any colour combination you and your partner wish, as long as you display the triangles flat on the table.

Please do not bend, twist or attach the pipe cleaners; you must use them as they are. Make sure the tips of the pipe cleaners are touching to create closed polygons. You can use different coloured pipe cleaners to create your triangle or you can use all the same colours.

Each partner group must try to make at least two triangles. Please remember this is a math activity, so all conversations should be related to creating your triangles. Once we have finished, the class will take part in an observation walk where we will circulate around the room and look at the triangles we have created.

You have three minutes to work with your partner to create as many triangle combinations as you can. Please begin.

Prompts

You’re on the right track.

It’s a great idea to use all different colours.

Is there a different way to make this triangle?

Please keep this one to the side.

______ is working really hard on her triangles.

I like the way ______ and ______ are focused during this activity.

Please show your group members how you made that triangle.

What about making a triangle that is bigger or smaller?

You can take those apart now and make different ones.

Please refer to the board if you are unclear about the instructions.

Time for an Observation Walk

Considering there are two groups, this is group one and this will be group two. When I ask, I want you to stand up. The members of group one are going to walk around and look at group two’s triangle creations. At the same time, group two is going to walk around the table of group one members to see their triangle creations. When we are observing something we are using our eyes only! Discussions will take place later in the lesson. As you walk around, please take a mental picture of the various triangles you observe.

Prompts

Please remember to use your eyes only!

Excuse me, please read the instructions on the board.

Equilateral Discussion

As I was walking around, I saw some really great examples of triangles I am now going to choose some students to come up and draw what they have created. Remember to use the same colours up here that you used in your pairs. Please look for similarities in the examples given. ______, please come up and draw your triangle for the class. (Repeat three times.) (To class:)

What do you notice about the sides of this triangle? (Pause for answer.) Do you remember what each colour represents? Yes, if all sides are the same colour, it means that all sides are the same length. So this triangle has sides that are all the same length. Does anyone know the name of this type of triangle?

(Show Slide #11 and read the definition.)

Grade 5s? Why do you think there are lines on each side of the shape?

You are right. These lines are used as a symbol to tell us that all sides are equal in length.

Isosceles Discussion

Let’s see more examples of triangles you created. Please look for similarities in the examples given. ______, please come up and draw your triangle for the class. (Repeat three times).

(To class:) What do you notice about the sides of this triangle? Do you remember what each colour represents? Yes, if all sides are the same colour, it means that all sides are the same length. So, this triangle has two sides that are equal in length. Does anyone know the name of this triangle?

(Show Slide #13 and read the definition.)

This is called an isosceles triangle. Do you remember why there are lines on the sides of the shape? These lines are symbols that show two sides are the same length and one side is different.

Scalene Discussion

Let’s see more examples of triangles you created. Please look for similarities in the examples given. ______, please come up and draw your triangle for the class. (Repeat 3 times.)

(To class:) What do you notice about the sides of this triangle? Do you remember what each colour represents? Yes, if all sides are the same colour, it means that all sides are the same length. So this triangle has no sides that are the same length. Do you know the name of this triangle?

(Show Slide #16 and read the definition.)

This is a scalene triangle. What do you notice about the symbols on each side of this triangle?

Prompts

How are they different?
What does that mean?
Can I see some different hands up please?

Yes. This triangle has sides that are three different lengths.

Find Examples

Now that we have learned about three types of triangles, let’s see if you can find examples of each in the original pictures. (Show Slide #3.)

What type of triangle do you see in this picture? Please come up and outline it. What makes it a ______ triangle?

Question

What is the difference between a scalene, isosceles and equilateral triangle? Use words and pictures to explain your answer.