Question

What should come in place of both x in the equation $\frac{x}{\sqrt{128}}=\frac{\sqrt{162}}{x}$.

• A. 12
• B. 14
• C. 144
• D. 196

Answer 1

Answer: (A)

12

Let $\frac{x}{\sqrt{128}}=\frac{\sqrt{162}}{x}$
Then, $x^2=\sqrt{128\times 162}$
$=\sqrt{64\times 2\times 18\times 9}$
$=\sqrt{8^2\times 6^2\times 3^2}$
$=8\times 6\times 3$
$=144$
$\therefore x=\sqrt{144}=12$.