Archive for February, 2012

Using Geogebra to Geometrically Prove Pythagorean Theorem

Hi all,

Below is the common geometric proof of pythagorean theorem. The idea is that since the sum of the areas of the triangles doesn’t change between these two squares, the total of the hatched areas does as well. Therefore The area of the square on the left – who’s side is represented by the hypotenuse of the 4 identical right triangles – must be the same as the area of the little square on the right (who’s one side is “a” units) plus the larger square on the right (who’s area is b units). In other words a^2+b^2=c^2.

The tutorial below shows how to create the diagram above using geogebra as an interactive simulation (changing the sliders changes the shape of the triangles, yet the property always stays the same):

 

The recording cut out at the end, but the only things I did after that part were purely asthetic.

Cheers,

Doug

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February 23, 2012 at 9:45 pm 1 comment

The Mathematics Online Planning Guides are now on Learnalberta.ca

Hi all, 

Several of you have been asking where the rest of the Mathematics Planning Guides are. Here’s a brief screencast about how to find all of them from K-9. 

  1. Browse to http://learnalberta.ca
  2. Create a teacher account if you don’t already have one, and log in.
  3. Click on the Programs of Study tab.
  4. Find K-9 Mathematics
  5. Find the outcome you are working on.
  6. Click the apple icon and choose “Planning Guide”

As always, let me know if you have questions…

Doug

February 21, 2012 at 8:33 pm 1 comment

Using Google Docs to create a live interactive Venn Diagram for Moodle

Hi all,

I used this trick in a workshop I facilitated last week. Rather than using chart paper to collect ideas as a Venn Diagram I created a live Venn Diagram using Google Docs and linked to it via our moodle page. Here are the basic steps I used, but the screencast below takes you through the whole process:

  1. Create a GMail account and use it to sign in to Google Docs 
    • Create a New Drawing in Google Docs
    • Draw 2 circles overlapping and use the paint function to make them partially transparent.
    • Use the text tool to label the circles
  2. Click share and change the privacy settings to “Anyone with the link”
  3. Copy the URL provided to your clipboard
  4. Turn editing on in your Moodle classroom and select Add a resource -> URL
  5. Give the link a description and paste in the URL you copied in step 3.

Here’s the whole process as a screencast. Enjoy. 🙂

Cheers,

Doug

February 10, 2012 at 6:35 pm 4 comments


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