Geometry & MeasuresIntroduction

No Height? No Problem!

Part of Area of Triangle (Trig) · GCSE GCSE Mathematics revision

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.

Topic position

Section 1 of 4

Practice

12 questions

Recall

2 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!

Keep building this topic

Read this section alongside the surrounding pages in Area of Triangle (Trig). That gives you the full topic sequence instead of a single isolated revision point.

The Formula Worked Example Knowledge Organiser: Area of Triangle Using Trigonometry

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?

A. Area = ab sinC
B. Area = ½ab sinC
C. Area = ½ab cosC
D. Area = ½(a + b) sinC

1 markfoundation

Starting from Area = ½ × base × height, show how to derive the formula Area = ½ab sinC.

2 marksstandard

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.

12 questions on Area of Triangle (Trig) — practise free

Instant marking, adaptive difficulty, and 2 spaced repetition flashcards. Free until your GCSEs.

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Area of Triangle (Trig)

The Formula