Question

The diameter of a wheel of a car is 70 cm. How many revolutions will it make to travel 99 km

Answer 1

Solutions :-

Diameter = D

π = 22/7

Given :- Diameter of a wheel of a car is 70 cm

Find the circumference of  wheel :-

Circumference of a circle = πD

= 22/7 × 70 cm

= 22 × 10 cm

= 220 cm

Find the number of revolutions of a wheel of a car to covers 99 km :-

Convert km into cm :-

99 km = 99 × 100000 cm = 9900000 cm

Now,

Number of revolutions

= Total distance/circumference of wheel

= 9900000/220

= 45000

Hence,

The wheel revolves 45000 times to travel 99 km.

Answer 2

Given Data of Wheel -

Diameter = 70 cm

Radius = Diameter / 2 = (70 / 2) cm

= 35 cm

∴ Circumference of wheel

= 2Πr

= [ 2 × 22 / 7 × 35 ] cm

= [ 2 × 22 × 5 ] cm

= 220 cm

Distance travelled by the wheel

= 99 km

= (99 × 100,000) cm

= 9,900,000 cm

∴ Number of Revolutions

=Distance Travelled/Circumference of Circle

= 9,900,000 cm / 220 cm

= 9,900,000 / 220

= 45,000

Hence, the wheel will take 45,000 complete revolutions to travel 99km.

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