Work with similar compound triangles in Similar Triangles (B). Here students will prove triangles are similar as well as calculate missing lengths in similar triangles.

In section A, learners will prove that three pairs of triangles are similar by using angle in parallel line rules and considering the ratio of corresponding lengths to find the condition for similarity.

Next, students calculate missing lengths in similar triangles. Questions consist of triangles within triangles and vertically opposite triangles.

Challenge your pupils with section C, made up of two questions where students may want to use algebra to find three missing lengths.