Page 223 - ICSE Math 8

11. Find the approximate length (in cm) of the minute hand of
the clock given that the tip of the minute hand covers 62 cm
in one rotation.
(Hint: Take p = 3.14)
12. The tyre manufacturing companies check its durability by rotating the tyre off the road using an
endurance test machine and measuring the distance covered by it till it is damaged. If the radius of a
wheel is 15 cm and it makes 50,000 revolutions before getting damaged, then find the durability of the
tyre.

THINK SMART

1. A metal worker cuts out a large semicircle with a diameter of 28 centimetres.
Then the metal worker cuts a smaller semicircle out of the larger one and removes
it. The diameter of the semicircular piece that is removed is 14 centimetres.
Find the distance around the shape after the smaller semicircle is removed. Use P 14 cm O 14 cm Q
3.14 for p and round to the nearest tenth.
2. A greeting card is made up of three semicircles. O is the centre of the large
semicircle. Sarah wants to decorate the distance around the card with a ribbon. A 5.2 in O 5.2 in B
How much ribbon does Sarah need? Use 3.14 for p and round to the nearest
tenth.

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