A circle has a diameter of 21 cm. Find its circumference.

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A 66 cm
B 33 cm
C 21 cm
D 42 cm

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Answer: A. 66 cm

Circumference = pi x diameter = 22/7 x 21 = 22 x 3 = 66 cm. Option b, 33 cm, would be the answer if you used the radius in place of the diameter.

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A circle has a diameter of 21 cm. Find its circumference.

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