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Do now: Work out the circumferences and areas of these circles. 2 cm. 10 cm. 1.5 cm. 9 cm. 12 cm. How well did you do?. C = 6.3 cm. 2 cm. 10 cm. C = 31.4 cm. 1.5 cm. C = 9.4 cm. 9 cm. 12 cm. C = 56.5 cm. C = 37.7 cm. How well did you do?. A= π × 1 2 A = 3.1 cm 2. 2 cm.
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Do now: Work out the circumferences and areas of these circles 2 cm 10 cm 1.5 cm 9 cm 12 cm
How well did you do? C = 6.3 cm 2 cm 10 cm C = 31.4 cm 1.5 cm C = 9.4 cm 9 cm 12 cm C = 56.5 cm C = 37.7 cm
How well did you do? A= π × 12 A = 3.1 cm2 2 cm 5 cm A= π × 52 A = 78.5 cm2 1.5 cm A= π × 1.52 A = 7.1 cm2 9 cm 12 cm A= π × 92 A = 254.3 cm2 A= π × 62 A = 113.0 cm2
Did you remember these important formulae? You are expected to remember these in your GCSE exam. Circumference = π × diameter C=πd OR Circumference = 2 × π × radius C=2πr Area = π × radius × radius A=πr2 diameter radius