MathematicsChapter 10: Tangents and Angles of a Circle
Number
R=13, r=5: half-chord 12, chord 24.
Learning objectives
- Define and explain number.
- Apply number to a focused FBISE question.
- Check the answer for correct terms, evidence, working, and units.
Definition
R=13, r=5: half-chord 12, chord 24. Same 5-12-13 triangle as chord-from-centre questions.
Formula
R=13
Where / symbols
- Number
- R=13, r=5: half-chord 12, chord 24. Same 5-12-13 triangle as chord-from-centre questions.
Overview
Learn the idea, then use it:
Core Understanding
R=13, r=5: half-chord 12, chord 24. Same 5-12-13 triangle as chord-from-centre questions.
Examples Pythagoras again · same centre · outer chord tangent to inner · NUMBER: R=13, r=5: half-chord 12, chord 24. Same 5-12-13 triangle as chord-from-centre questions.
Exam Application
State the correct term, connect it to the chapter rule or evidence, and use a clear example or calculation.
Examples Define first · Show the rule or evidence · Check units, labels, and conclusion
WHAT — NUMBER
R=13, r=5: half-chord 12, chord 24. Same 5-12-13 triangle as chord-from-centre questions.
HOW — Use the idea
Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check the result.
In simple words
Do not merge number with a neighbouring idea that uses a different definition, rule, or method.
Key points
- Pythagoras again
- same centre
- outer chord tangent to inner
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Number
Sticky Notes · Quick Revision
Core Idea
- R=13, r=5: half-chord 12, chord 24.
Key Points
- Pythagoras again
- same centre
- outer chord tangent to inner
Simple Check
- Explain number in your own words and connect it to one chapter example.
How to Answer
- Define the idea, show the main rule or evidence, apply it, and check the final statement.
Common Mistake
- Do not merge number with a neighbouring idea that uses a different definition, rule, or method.
FBISE Exam Tip
- Use the exact term, show working where needed, and include units or labelled evidence.
60-second revision
- R=13, r=5: half-chord 12, chord 24.
- Pythagoras again
- same centre
- outer chord tangent to inner
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