If $\sqrt{33} = 5.745$, then the value of the following is approximately $\sqrt{\frac{3}{11}}$
Aptitude
Square Root and Cube Root
Difficulty: Medium
Choose an option
-
A1
-
B6.32
-
C0.5223
-
D2.035
Answer
Correct Answer: 0.5223
Explanation
Concept & Formula
To find the value of a fraction under a square root when given the root of a related product, rationalize the denominator of the fraction inside the square root to match the given information.
$$ \sqrt{\frac{a}{b}} = \frac{\sqrt{a \times b}}{b} $$
Step-by-Step Solution
* **Given:** $\sqrt{33} = 5.745$ and we need to evaluate $\sqrt{\frac{3}{11}}$
* **Calculation:**
To utilize the given value of $\sqrt{33}$, multiply the numerator and the denominator of the fraction inside the root by 11.
$\sqrt{\frac{3}{11}} = \sqrt{\frac{3 \times 11}{11 \times 11}}$
* Simplify the expression:
$= \sqrt{\frac{33}{121}}$
* Apply the square root to the numerator and denominator separately:
$= \frac{\sqrt{33}}{\sqrt{121}}$
$= \frac{\sqrt{33}}{11}$
* Substitute the given value:
$= \frac{5.745}{11}$
* Perform the division:
$5.745 \div 11 = 0.52227...$
* Round to four decimal places as seen in the options:
$\approx 0.5223$
Exam Strategy & Shortcut
Whenever you are given the value of $\sqrt{a \times b}$ and asked for $\sqrt{a/b}$, the fastest shortcut is to multiply the top and bottom by $b$. This immediately gives you $\frac{\sqrt{ab}}{b}$. Here, it turns $\sqrt{3/11}$ into $\frac{\sqrt{33}}{11}$, turning a complex square root problem into a simple division problem.
Common Pitfall
A common mistake is trying to independently estimate the values of $\sqrt{3}$ and $\sqrt{11}$ and divide them. While this works mathematically, it is highly prone to rounding errors and takes significantly more time than using the provided value of $\sqrt{33}$.
Final Answer
**Therefore, the correct answer is 0.5223.**