Question

Question 111

Solve the following question:

A decimal number is multiplied by itself. If the product is 51.84, then find the number.

Answer 1

Let the number be $x$. Then, product $=x\times x=x^2$
But product = 51.84 [given]
$\therefore x^2=51.84$
$\Rightarrow x=\sqrt{51.84}$
Now, place the bar over the numbers, then square root is given below.
$\begin{array}{cc}& 7.2\\ 7& \overline{51}.\overline{84}\\ & 49\\ 142& 284\\ & 284\\ & 0\end{array}$

$\therefore$ $x=\sqrt{51.84}=7.2$
Hence, the required number is 7.2.