## Wednesday, 7 October 2015

### MPM2D - Day 21: Intro to Trig

I talked very little in today's class because my students were busy working. They started with the similar triangle word problems that I had handed out at the end of yesterday's class. I had them write the answers on the board and if there were two different answers for the same question, someone wrote their solution on the whiteboard. It all went very smoothly - they didn't have many questions.

Once most students had finished those questions, we moved on to trig. They have never encountered trig before so we are starting fresh. I like to introduce it with act I of this (Boat on the River) 3-act from Andrew Stadel

They quickly got to the question:

We talked about why, as the captain of this ship, this would be an important issue to figure out before attempting to fit under the bridge. In order to calculate that angle...

I like to throw in a bit about how trig is actually used in "real life".

After we discussed how to name the sides of a right triangles (opposite, adjacent & hypotenuse), I had them work in groups to make their own trig tables. With the help of protractors, they had to draw triangles, then measure and record the sides lengths. They then had to calculate the ratios of sides. Here's my version of the table they were working on, found in this handout.

There were some good questions along the way as I circulated that could be paraphrased "Does it matter what size my triangle is?". That's as far as we got today. Here is homework set 18.