IB Maths AA SL 3.2 - Triangle Rules

This IB Maths AA SL Topic 3.2 – Triangle Rules resource develops students’ confidence in solving problems involving right-angled and oblique triangles. It begins by reviewing the sine, cosine, and tangent ratios through SOHCAHTOA, with a clear reminder that these methods apply only to right-angled triangles. Students then learn when and how to use the sine rule and cosine rule to calculate missing sides and angles in non-right-angled triangles.

The lesson also introduces the formula for the area of a triangle using two sides and the included angle. Students practise selecting the appropriate rule from the information provided and applying it accurately in both mathematical and real-world contexts, including ladder problems and multi-part triangle questions. With clear formula summaries, labelled diagrams, worked examples, contextual practice, and fully worked solutions, this resource helps SL students build strong problem-solving skills with triangle geometry in line with IB Mathematics AA expectations.