Question

If the volume of the above cubic block is $9$ cubic ft, then the length of each side of the cube will be ___________.

• A. an irrational number
• B. a whole number
• C. a rational number
• D. an integer

Answer 1

The correct option is A an irrational number

Detailed step-by-step solution:
The volume of the above cubic block $=9$ cubic ft
Formula to find the volume of a cube $=a^3$ (if length of sides $=a$)
Hence, $a^3=9$.
Taking cube root on both the sides,
$\Rightarrow \sqrt[3]{3a^3}=\sqrt[3]{39}$
$\Rightarrow a=\mathrm{2.08008...}$ (by using calculator)
Here, $2.08008\dots$ is a non-terminating non-recurring decimal number.
Hence, $2.08008\dots$ is an irrational number.