Circumference of a circle

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Circumference of a circle Perimeter of a circle Saturday, 06 April 2019

Example Taking the piece of string measure the circumference of the circular face on the tin. With your ruler now measure the diameter. Work out 𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑓𝑎𝑐𝑒 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑐𝑖𝑟𝑐𝑙𝑒

𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒=𝜋𝐷 Diameter Example Work out the circumference of a circle whose diameter is 8cm, giving your answer correct to 2 decimal places. C=𝜋𝐷 𝐶=𝜋 ×8 𝐶=25.13 𝑐𝑚

Example Work out the circumference for each of the following circles, giving your answers correct to 1 decimal place. (i) (ii) 3.6m 12cm

(iii) (iv) 20cm 13cm

Example Work out the perimeter of the semicircle drawn below. Give your answer correct to 2 decimal places. 15cm

Example Given that the Circumference of a circle is 100cm, work out the diameter of this Circle.