To determine which expression is rational, we need to identify if the numbers can be expressed as a fraction of two integers.
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4.121221222... - This is a repeating decimal, which means it can be expressed as a fraction. Therefore, it is rational.
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Square root of 36 - This equals 6, which is an integer. All integers are rational numbers because they can be expressed as a fraction (6/1). Thus, this is rational.
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Square root of 21 - This is an irrational number because it cannot be expressed as a fraction of two integers. Therefore, it is not rational.
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1.192744502... - This is a non-repeating decimal, which means it cannot be expressed as a fraction of two integers. Therefore, it is not rational.
Based on this analysis, the expressions that are rational are:
- Square root of 36 (6)
- 4.121221222...
If you are looking for just one example, square root of 36 is definitely rational and straightforward because it equals a whole number (6).