They worked fairly quickly, so also as a demonstration of the homework, I quickly made up 6 other non-unit triangles for them to work on. Pupils out to the board to write up the working. Pupils to say which letter to use for the sides. Pupils to rearrange the formulae at the board, with the consent of the class. These would be given to you on an exam paper, but in terms of sin , cos or tan .
Second pupil draws up one of their examples.
They had no problem abstracting their working for the first 3 triangles into formulae to find the sides they had been looking at so far. The next rearrangement needed a little prompting about dividing both sides, but we got there in the end. The third rearrangement sparked memories or images of things they had seen or experienced before. It was all coming together quite nicely. They were happy applying the formulae to their examples, however I had to intervene and make changes to their examples.