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Find the diameter of a circle whose circumference is(i) 12.56 cm(ii) 88 m(iii) 11.0 km |
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Answer» (i) Given circumference, C = 12.56 cm We know that the circumference of the circle = 2 π r Therefore radius, r = C/2 π r = (12.56 × 7)/ (2 × 22) r = 87.92/ 44 r = 1.99 cm But diameter = 2r = 2 × 1.99 = 3.99 cm (ii) Given circumference, C = 88 m We know that the circumference of the circle = 2 π r Therefore radius, r = C/2 π r = (88 × 7)/ (2 × 22) r = 616/ 44 r = 14 m But diameter = 2r = 2 × 14 = 28 m (iii) Given circumference, C = 11.0 km We know that the circumference of the circle = 2 π r Therefore radius, r = C/2 π r = (11 × 7)/ (2 × 22) r = 77/ 44 r = 1.75 km But diameter = 2r = 2 × 1.75 = 3.5 km |
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