| Area | = (1/2) × a × b × sin C |
| Where | C is the INCLUDED angle (between sides a and b) |
| Also written as | (1/2)ab sinC or (1/2)bc sinA or (1/2)ac sinB |
This key facts covers The Formula within Area of Triangle (Trig) for GCSE Mathematics. Revise Area of Triangle (Trig) in Geometry & Measures for GCSE Mathematics with 12 exam-style questions and 2 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 2 of 4 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Area of Triangle (Trig)
What is the trigonometric formula for the area of a triangle with sides a and b and included angle C?
Starting from Area = ½ × base × height, show how to derive the formula Area = ½ab sinC.
Quick recall flashcards
Trig Area Formula
Area = (1/2)ab sinC. The angle MUST be between the two sides you're using.
Area with Trig
Area = ½ab sin C