The Cosine Rule — Practice Companion

Eight exam-style questions on the cosine rule (both side-finding SAS and angle-finding SSS). Whenever you're stuck, you have four kinds of help, in this order:

🤔 Socratic prompt — a question to get you thinking. 💡 Hint — a piece of method. ✅ Check my answer — try as many times as you like. 👀 Worked solution — the full method, unlocked once you've genuinely tried.

Give angles in degrees to 1 decimal place and lengths to 2 decimal places unless told otherwise. Calculator must be in degrees mode.

💛 Reflection

Before you close this, take a moment:

When the cosine rule's correction term came out negative, did you anchor that back to "C must be obtuse" — or just compute and trust? Both are fine, but the anchor is faster.
Which feels more confident now — picking when to use the sine rule, or picking when to use the cosine rule? Whichever feels less confident is what to practise more.
If you taught one of these questions to a friend, which would you choose, and why?

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The Cosine Rule — Practice CompanionPure 1, Trigonometry · Lesson 2

💛 Reflection

The Cosine Rule — Practice Companion
Pure 1, Trigonometry · Lesson 2