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10. The tyre of a car wheel has an outer diameter of 30 cm. How many times will the wheel rotate on a journey of 5 km? |
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Answer» -step EXPLANATION:The diameter is 30 cm, therefore the radius is 15 cm. The CIRCUMFERENCE of the TIRE is found by using the formula C = 2πr. C ≈ 2(3.14)(15) ≈ 94.2 cm. 5 km = 500,000 cm (5 x 1000 x 100). 500,000 ÷ 94.2 ≈ 5307.86 or about 5300 TIMES (revolutions). (using π, INSTEAD of 3.14, I got 5305.16 revolutions) |
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