This introduction covers No Height? No Problem! 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 1 of 4 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
No Height? No Problem!
The usual area formula (1/2 × base × height) needs the perpendicular height. But what if you only know two sides and the angle between them? The trig area formula saves the day!
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
Area with Trig
Area = ½ab sin C
Trig Area Formula
Area = (1/2)ab sinC. The angle MUST be between the two sides you're using.