0.167 is rational since either
scenario A) 0.167 terminates meaning it's equal to 167/1000
OR
scenario B) 0.167 is a rounded version of 0.166666666.... which means it's equal to 1/6
Either way, 0.167 is rational
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2/9 is rational since it is a fraction of whole numbers
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π (or "pi") is irrational because we cannot write this as a fraction of whole numbers
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Because 225−−−√=15=151 tells us that 225−−−√ is rational.
Hope this is what your looking for!!