This is an excellent lesson looking at where the cosine rule comes from, when to use it and how to use it. 19 slides.
It includes a starter, lesson objectives, an explanation of where the rule comes from and how and when to use the rule. It includes very clear teaching slides and also common mistakes made when using the rule. It includes exam-style questions (which also consolidates the sine rule, as I teach that the lesson before). It comes with answers with workings and a plenary.
This lesson has been adapted over the years and is very structured and organised. I often teach this lesson over two lessons as there is a lot of material here. This is part of an excellent trig bundle, which I highly recommend as a sequence/series of lessons.
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