To determine which of the sums results in a rational number, let's analyze each option.
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π + √4
- π (pi) is an irrational number. √4 = 2 is a rational number. The sum of a rational and an irrational number is irrational. Therefore, this sum results in an irrational number.
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0.6̅ + 9/10
- The repeating decimal 0.6̅ represents the rational number 2/3. Adding 2/3 (the rational form of 0.6̅) to 9/10 (which is also rational) results in a rational number. Therefore, this sum results in a rational number.
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√36 + √221
- √36 = 6, which is a rational number. √221 is an irrational number (since 221 is not a perfect square). Adding a rational and an irrational number results in an irrational number. Therefore, this sum results in an irrational number.
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0.643892553… + 3/4
- The decimal 0.643892553… appears to be a non-repeating decimal, indicating it is likely an irrational number. Adding an irrational number (if 0.643892553… is indeed irrational) to the rational number 3/4 will result in an irrational number. Therefore, this sum results in an irrational number.
From this analysis, the only sum that results in a rational number is:
0.6̅ + 9/10.