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Radius, diameter and circumference
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Radius, diameter and circumference
Radius, diameter and circumference
Example 1
A circle has radius 2cm. Find its diameter, in cm.
Show worked answer
Answer: 4
- The diameter is twice the radius: 2×2=4cm.
Example 2
A circle has diameter 6cm. Its circumference is kπcm. Find k.
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Answer: 6
- C=πd=6πcm, so k=6.
Example 3
A circle has diameter 7cm. Find its circumference, in cm. Use π=3. Give an exact answer.
CircleDiagram not to scaleShow worked answer
Answer: 21
- Circumference =πd.
- Using π=3:3×7=21cm.
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