Question

The diameter of a bicycle wheel is 28 cm. what distance will it cover in 100 revolutions?

Answer 1

Hint: The circumference of the bicycle represents the distance that will cover in 1 revolution and the radius is half of the diameter i.e. $r = \dfrac{d}{2}$.
The formula to find the distance covered in n revolution = circumference of the bicycle $\times $ number of revolutions.

Complete step by step answer:
The diameter of a bicycle is 28 cm, and we know that radius is half of the diameter
Therefore, $r = \dfrac{d}{2}$
$
\Rightarrow r = \dfrac{{28}}{2} \\
\Rightarrow r = 14cm \\
 $
Now, the circumference of the bicycle = the distance it covers in one revolution= $2\pi r$
 The distance it covers in one revolution= $2\pi r$
$= 2 \times \dfrac{{22}}{7} \times 14 \\
   = 88cm \\ $
So it covers the distance of 88 cm in 1 revolution.
Let n be the number of revolutions.
The formula to find the distance covered in n revolution = circumference of the bicycle $\times $ n (no. of revolution).
The formula to find the distance covered in n revolution $= 88 \times n$
(here, n is the number of revolutions)
Similarly, it covers the distance in 10 revolution $=88 \times 10 cm$
So, now the distance it will cover in 100 revolutions $= 88 \times 100 $
$ = 88,00cm $

$\therefore$ In 100 revolutions, the bicycle wheel covers 88,000cm.

Note:
The circumference is how far the wheel goes in 1 revolution. Take the value of pie as 22/7 for easy calculation. The distance around the circular region is called its circumference and the major of the region enclosed inside the circle is called its area so to find the revolution we evaluate the circumference of the bicycle.