A rational number is any number that can be expressed as a fraction \( \frac{a}{b} \), where \( a \) and \( b \) are integers and \( b \neq 0 \). Let's analyze each option:
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\( 2\pi \): Pi (\( \pi \)) is an irrational number. Therefore, \( 2\pi \) is also irrational.
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60: This is an integer, and it can be expressed as \( \frac{60}{1} \), making it a rational number.
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\( \sqrt{61} \): The square root of 61 is not a perfect square, hence \( \sqrt{61} \) is an irrational number.
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0.37815: This is a terminating decimal, which can also be expressed as a fraction (e.g., \( \frac{37815}{100000} \)). Therefore, it is a rational number.
Based on the analysis, the rational numbers in the list are:
- 60
- 0.37815
Thus, among the options provided, 60 is a rational number.