angle a-trons.pptx

Angle-a-tronsAnica Trickovic

I got inspiration for this class from a video on Khan academy called “Angle-a trons”

Link for this video:

https://www.khanacademy.org/math/recreational-math/vi-hart/spirals-fibonacci/v/angle-a-trons

What does the word “angle-a-trons” means?

•the suffix "-tron" denotes a complex scientific instrument

• angle models made of paper

Description of the lesson

Are there any angles on this piece of paper?

90° angle 180° angle

What about this irregular piece of paper?

With one fold we can turn it into 180° angle-a-tron

90° angle we can get

by folding a 180° angle-a-tron in half

45° angle we can get by folding a 90° angle-a-tron in half

22,5° angle we can get by folding a 45° angle-a-tron in half

and so on…

It’s not hard to fold the paper in thirds either

We can get an angle of 60° by folding 180° on three equal parts

60° angle-a-tron

By folding 60° angle-a-tron into half

we can get an angle of 30°

Then we get an angle of 15° by folding 30° angle-a-tron in half

We can add them together…

We can put two angles of 60° together to get 120° angle-a-tron

We can get 135° by adding 90° and 45°

Together with students we make all angle models from paper.Students check the angles with their protractors after they make the models.

Activities for students

Students are divided into four groups

Every student draws a picture, using just one ruler and angle-a-trons which they made. If they have time, they can colour the drawings. Students can help each other .

Group 1:

Use angle-a-tron of 90°

Group 2:

Use angle-a-trons of 90° and 45°

Group 3:

Use angle-a-tron of 60°

Group 4:

Use angle-a-tron of 120°

Every group chooses the best drawing which will be displayed on the classroom wall.

Summary

I remembered when I was a student that my teacher showed us how to make angle-a-trons.

We usually don`t carry around a protractor, so this can be useful to the students because they can make their

own angle models.

In the same time, students can see the size of the most used angles 180°, 90°, 45°; ...,60°, 30°, 15°,...

I think the students will specially like the drawing activity using rulers and angle-a-trons made of paper.