Question

The diameter of a cycle wheel is 21cm. How many revolutions it will take to travel 1.98km

Answer 1

Given that the diameter = 21 cm


We need to find out the circumference first


Circumference of a circle

= 2πr

= πd

Where d is the diameter.


So circumference = πd

=>
$\frac{22}{7} \times 21 \\ \\ = >22 \times 3 \\ \\ = > 66$

Circumference of the circle = 66 cm


Now the wheel has to travel 1.98 km

We need to convert km to cm

1 km = 100000 cm

=> 1.98 km = 198000 cm


So number of revolutions = Distance/Circumference

= 198000/66

= 3000

Hence your answer is 3,000

Hope it helps dear friend ☺️✌️✌️