Rational and Irrational Numbers Practice
Math 8 Q1 (Pre-Algebra) / The Number System
Which of the following is a rational number: 32−−√, 81−−√, 90−−√, or 125−−−√?(1 point)
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The rational number is $\boxed{81^{-\frac{1}{2}}}$.
To determine whether a number is rational or irrational, we need to check if it can be expressed as a fraction.
The square root of 32 is approximately 5.657, so 32−−√ is irrational.
The square root of 81 is 9, so 81−−√ is rational.
The square root of 90 is approximately 9.49, so 90−−√ is irrational.
The square root of 125 is approximately 11.180, so 125−−√ is irrational.
Therefore, the only rational number among the options is 81−−√.