KS4 / GCSE · Mathematics — Higher

Trigonometry

What Is It

GCSE Higher trigonometry extends SOH CAH TOA to non-right-angled triangles using the sine rule and cosine rule, and covers finding the area of a triangle using ½ab sin(C).

Why It Matters

The sine and cosine rules unlock a much wider range of real-world triangle problems — surveying, navigation, engineering — that can't be solved with basic SOH CAH TOA alone, since most real triangles aren't right-angled.

Exam Tip

Before choosing a formula, check whether the triangle is right-angled (use SOH CAH TOA) or not (use the sine or cosine rule) — picking the wrong toolkit for the shape of the triangle is the most common trigonometry mistake.

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