Circumference of a Circle
The circumference of a circle is the length of its curved boundary.
Practice This ConceptMain explanation
Teacher explanation
A circle has no straight sides, so its perimeter is called circumference. It depends on the radius or diameter and uses pi, written as π.
Example
For radius 7 cm, circumference = 2πr = 2 × 22/7 × 7 = 44 cm.
Simple analogy
Circumference is the circle's outside boundary.
Common confusion
Students often use πr² and calculate area when the question asks for circumference.
Exam tip
If the answer is boundary length, use 2πr or πd, not πr².
Answer writing and exam use
1-mark use
Write the exact meaning of circumference of a circle in one clean line.
2-mark use
Define circumference of a circle and add one example or condition.
3-mark use
Explain circumference of a circle, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
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