Question

The bookshelf in our classroom is three and a half feet long. How many inches tall is it ?

Answer 1

Hint: Here this question belongs to the conversion topic, that is we have to convert the unit from one form to another. Here we have to convert the unit feets into unit inches. In the question, we have to find what number of inches correspond to three and a half feets.

Complete step by step solution:
The feet and inches are the units to measure the length of physical commodities or items. A feet is abbreviated as ft and inches is abbreviated as inch. A inch is a metric unit of length and it is used for measuring small lengths.
The given question requires us to convert the unit of length. We have to convert three and a half feet into inches.
We know that each feet of length consists of $12$ millimetres. So, $1\,feet = 12\,inches$.
Let the number of inches that correspond to three and a half feet be x.
Then, to convert $3\dfrac{1}{2}$ feets into inches, we follow unitary method where we first find that how many units of inches correspond to a single unit of feet and then multiply both sides of the equation by a suitable number so as to get the desired conversion of $3\dfrac{1}{2}$ feet.
So, $1$ feet $ = $ $12$ inches
Now, we know that $3\dfrac{1}{2}$ can be written as $\dfrac{7}{2}$ in improper fraction form.
Hence, $3\dfrac{1}{2}$ feet $ = 12 \times \dfrac{7}{2}$ inches
$ \Rightarrow 3\dfrac{1}{2}$ feet $ = 6 \times 7$ inches
$ \Rightarrow 3\dfrac{1}{2}$ feet $ = 42$ inches

Hence, the bookshelf is $42$ inches tall.

Note: We have different units for solid quantity, liquid quantity and gaseous quantity. Every quantity has a measurement unit from the low quantity to the high quantity. While converting the unit of a quantity from one form to another form we have standard value. By multiplying or dividing we can convert the unit of the quantity. We have a different system of measurement of a quantity.