# Worksheet: Circumference of a Circle

Q1:

Work out the circumference of the circle given that , giving your answer accurate to two decimal places.

Q2:

Work out the circumference of the circle, giving your answer accurate to two decimal places.

Q3:

Using 3.14 to approximate , what is the diameter of a circle of circumference 125.6 cm?

Q4:

Using 3.14 to approximate and the fact that is a square, calculate the perimeter of the shaded part.

Q5:

Write this ratio in its simplest form: The ratio of the circumference of a circle to its radius.

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• D

Q6:

The formula for the circumference of a circle is . Rearrange this formula to make the subject.

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• B
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• E

Q7:

Work out the circumference of the circle given that , giving your answer accurate to two decimal places.

Q8:

Using to approximate , what is the difference in circumference between a circle of radius 77 cm and one of radius 63 cm?

Q9:

Using 3.14 to approximate , what is the difference in circumference between a circle of radius 30 cm and one of radius 15 cm?

Q10:

The circumference of a circle is a function of its diameter represented by the equation . If the diameter is the input and the circumference is the output, calculate the circumference when the diameter is 5.

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• C

Q11:

Find the circumference of a circle whose radius is 12.4 cm. Give your answer to the nearest centimetre.

Q12:

Using 3.14 to approximate , what is the difference in circumference between a circle of diameter 100 cm and one of radius 15 cm?

Q13:

Using 3.14 to approximate , what is the difference in circumference between a circle of diameter 80 cm and one of radius 15 cm?

Q14:

Using 3.14 to approximate , what is the circumference of a circle of diameter 34 cm?

Q15:

Answer the following questions for the circle shown.

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• B
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• E

Work out the area of the circle giving your answer in terms of .

• A
• B
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• D
• E

Q16:

Using to approximate , what is the difference in circumference between a circle of diameter 63 cm and one of diameter 49 cm?

Q17:

Work out the circumference of a circle with a diameter of 10 inches, giving your answer to two decimal places.

Q18:

Using 3.14 to approximate , what is the circumference of a circle where half of the diameter is 40 cm?

Q19:

Use in place of to decide: which is greater, the perimeter of a 9 cm by 17 cm rectangle or the circumference of a circle with radius 10 cm.

• Athe perimeter of the circle
• Bthe perimeter of the rectangle

Q20:

Use in place of to decide: which is greater, the perimeter of a 5 cm by 10 cm rectangle or the circumference of a circle with radius 12 cm.

• Athe perimeter of the circle
• Bthe perimeter of the rectangle

Q21:

What is the formula for the circumference of a circle with radius ?

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• B
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• D

Q22:

If the radius of a circle equals 13.8 cm, find the length of its longest chord.

Q23:

If the radius of a circle equals 22.4 cm, find the length of its longest chord.

Q24:

The formula for the circumference of a circle is . Find the circumference of a circle with a diameter of 12 in. Give your answer in terms of , knowing that the diameter is equal to .

• A in
• B in
• C in
• D in

Q25:

Find, to the nearest hundredth, the circumference of a circle of diameter 55.5 cm.