Day 3: Triangle centers

Today we're going to study the different triangle centers: centroid, incenter, circumcenter and orthocenter. I'm sure you studied them before. Are you able to remember them?

Links

• Triangle centers  (maths is fun)
• Triangle centers (geogebra tube)

Activity

Now that you have read about triangle centers, try to do the following activities.

Day 2: Triangles with geogebra

You already know that we can classify the triangles acording to their angles and acording to their side lengths. Read this link if you want to know more.

Activity

1.  Open geogebra and draw in the same canvas the following triangles:
• Equilateral triangle
• Isosceles triangle
• Scalene triangle
• Save the .ggb file
2.  Open another geogebra file and try to draw the following triangles:
• Acute triangle
• Obtuse triangle
• Right triangle
• Save the .ggb file
3. Questions:
1. Draw here a short definition for each kind of triangle according to their side lengths.
2. In the second file, use then the angle utility of geogebra and measure each angle. How much is the sum of the 3 angles of a triangle?
4. Send an email to the teacher with the two .ggb files attached and the answer to the questions.

Day 1: Learning Geogebra!

Geogebra is an opensource multiplatform program that lets students experiment with geometry and maths in general. This trimestre we are going to learn the basic tips of this fantastic tool.

Activity 3.1

Sit in couples together. Try to make a drawing like the one in the picture. Save the .ggb file that you get. Send the file to the teacher.

Days 7 & 8: Let's summarize! Prepare your Tangram project presentation

Now it's time for summarizing. Take all what we have done and try to make a slide presentation using Impress or Prezi. You should gather in groups of 3 or 4 people. Next day you'll have to present it to all your class mates.

---

Items to be considered in the presentation

1. The tangram
• Origin of the game
• Pieces of the tangram:
• Shapes and their names
• Sizes of the pieces
• Areas of the pieces
2. Nice tangram constructions with their names
3. The Tangram cousin: the Stomachion
   • Origin
   • Pieces
   • Constructions with this Tangram
4. What's your opinion about this project? Did you like it? Why?
5. Vocabulary and expressions of the project

---

Your oral presentation will be evaluated according to the following rubrics.

Days 5 & 6: The Tangram Cousin. The Stomachion or The Archimedes puzzle

The Stomachion is a very ancient Tangram-like puzzle designed by Archimedes around the year 200 BC. Let's play a little bit in order to know something more about this puzzle. After that you'll have to fill in the following activities.

• More about the Archimedes puzzle

Day 4: Are you able to invent a story using 5 different tangram constructions?

Take your own tangram and try to build 5 different constructions. You don't need to use the ones of the picture, you can surf on the internet to find more. Draw the solution of the constructions on a piece of paper. Afterwards, try to invent a story in which all the created characters appear.

Day 3: The dimensions of the 7 Tangram pieces

Have you ever wondered how to compute the length of the sides of every tangram figure? To do so, first of all you should know what the Pythagoras theorem is. Watch the videos and do the following activity.