Teacher Notes

Why we like this activity

The use of dynamic geometry enables this introduction to trigonometry to move on quickly. I’m sure most of us have used this kind of introduction using paper and pencil before (and been frustrated by the lack of pace and the inaccurate constructions). Students quite naturally want to play around with the triangle and usually try to produce a triangle with the biggest angle possible which leads into a nice discussion about whether an angle A can be 90°.

How this activity can be used

The students can work individually, but sharing of results is essential.
A recap of similar triangles may be useful beforehand.

What to expect

Students need not have any prior experience of this software package.