Question

Find the value of the following.
 $12\mathrm{\%}$ of $1$ km in m.

Answer 1

Hint: $1$ Kilometre is equal to $1,000$ m as per standard units of measurement.
Kilometre and metre are measures of length.

Complete step by step answer:
Standard units of measurement for length in descending order are given as:
Kilometre, hectometer, decameter, metre, decimeter, centimeter, millimeter.
The conversion process works in both ways that higher units can be converted into lower units and vice versa. For instance, kilometre can be converted into metre and metre can be converted into kilometre.
For conversion of units, units to the left in above descending order have to be multiplied to be converted into units on the right. Similarly, to convert units of right into units on their left side, the division has to be done.
The a% of a number is calculated by multiplying a by the number and then dividing the obtained result by $100$.
The conversion of kilometre into metre is beneficial in calculating the standard measurements.
$12$ of $1$ km is calculated by multiplying $12$ by $1$ km. The value is calculated as:
$\begin{array}{rl}& \text{12 }\mathrm{\%}\text{ of 1 km = }\frac{12}{100}\times 1\text{ km}\\ & \text{=}\frac{3}{25}km\end{array}$
$12$ of a kilometre indicates twelfth part of a kilometre or it can be said as three by twenty-fifth of a kilometre.
As one kilometre is equal to $1,000$ metre, the expression $12$ of $1$ km when converted into metres is determined as:
$\begin{array}{rl}& \text{12 }\mathrm{\%}\text{ of 1 km into m = }\frac{3}{25}km\\ & =\frac{\text{3}}{\text{25}}\times \text{ 1,000 m}\\ & \text{= 120 m}\end{array}$
Therefore, $\text{12 }\mathrm{\%}\text{ of 1 km}$ when converted into metre is equal to $\text{120}$ m.

Note: A particular percentage of some number is calculated by multiplying the percentage by number and then divide the obtained result by $100$.
The operation “of” means multiply.