If $\sqrt{.00000676} = .0026$, the square root of $67,60,000$ is:
Aptitude
Square Root and Cube Root
Difficulty: Easy
Choose an option
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A1/26
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B26
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C260
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D2600
Answer
Correct Answer: 2600
Explanation
Concept & Logic
The significant digits of a square root remain constant if the original number is multiplied by an even power of $10$. You can extract the integer square root and append the appropriate number of zeros.
$$\sqrt{x \cdot 10^{2n}} = \sqrt{x} \cdot 10^n$$
Step-by-Step Solution
* **Given:** $\sqrt{.00000676} = .0026$. By moving the decimal 8 places to the right (multiplying by $10^8$), we can deduce that the square root of the significant digits is $\sqrt{676} = 26$.
* **Calculation:** We need to evaluate $\sqrt{6760000}$.
* Break the number down into known perfect squares: $\sqrt{676 \times 10000}$.
* Apply the square root separately to both parts: $\sqrt{676} \times \sqrt{10000}$.
* Substitute the known values: $26 \times 100 = 2600$.
Exam Strategy & Shortcut
Count the trailing zeros. The number $6760000$ has $4$ trailing zeros. Its square root will have exactly half that number of trailing zeros, which is $2$. The significant integer part is $\sqrt{676} = 26$, so simply attach two zeros to get $2600$.
Common Pitfall
Overcomplicating the problem by trying to reverse-engineer the decimal shift from the given equation, rather than just extracting the core significant root ($\sqrt{676} = 26$) and solving the new number independently.
Final Answer
**Therefore, the correct answer is 2600.**