Alyson:

In week 8 tutorial you will be allocated one of these Geometer’s sketchpad lessons to evaluate. You are to carry out the lesson and evaluate it (with a link to it included) on your blog. Ask yourself questions like: What part (if any) of the NSW syllabus would this lesson be appropriate for? What is the benefit of using the Geometer’s sketchpad software in this lesson? Could the lesson be taught any other way? If so, how? How could the lesson be improved? Are the instructions for the lesson clear?

Finding Relationships Between Area and Parallel Lines in Triangles

This lesson was alright. I couldn’t find the “Label Options” thing, so I don’t know if it was for a different Geometer’s Sketchpad than the one I was using. Apart from the slight differences, the instructions were very clear.

I guess the lesson is useful in cementing the idea of why area=1/2 the base times the perpendicular height. If students just remember the formula A=1/2bh they may not remember that the “h” stands for perpendicular height and may measure some obscure kind of height. This lesson proves that even if the triangle is incredibly stretched out, the height is still the same, and the formula tells us this because the base is staying the same, therefore if the height changed the area would change, but it doesn’t.

Trying to do this lesson without the help of Geometer’s Sketchpad would be very difficult. I think it is very handy in allowing students to see the ramifications of the formula for the area of a triangle in action. You really do need the software to move the point around and see that it doesn’t change. Drawing a billion different triangles within parallel lines with the same base would be tedious and not worth it.