Math Problem Statement

Select the expression that results in a rational number.

Solution

Let's break down each option to determine which expression results in a rational number:

A. 0.137137+93-0.137137 + \sqrt[3]{9}

  • 0.137137-0.137137 is a repeating decimal that can be expressed as a rational number.
  • 932.08008\sqrt[3]{9} \approx 2.08008 is not a rational number (because 9 is not a perfect cube).

Therefore, A does not result in a rational number.


B. 80+(0.6)\sqrt{80} + (-0.6)

  • 80=458.944\sqrt{80} = 4\sqrt{5} \approx 8.944, which is irrational.
  • 0.6-0.6 is rational, but since the square root of 80 is irrational, the entire expression is irrational.

C. 363+64\sqrt[3]{36} + \sqrt{64}

  • 3633.301\sqrt[3]{36} \approx 3.301, which is irrational.
  • 64=8\sqrt{64} = 8, which is rational, but because 363\sqrt[3]{36} is irrational, the whole expression is irrational.

D. 0.1+1690.\overline{1} + \sqrt{169}

  • 0.10.\overline{1} is a repeating decimal that can be expressed as 19\frac{1}{9}, which is rational.
  • 169=13\sqrt{169} = 13, which is rational.

Since both terms are rational, the entire expression is rational.

Thus, D is the correct answer. It results in a rational number.

Would you like further details or explanations on any step?

Here are 5 related questions to explore:

  1. What is the difference between rational and irrational numbers?
  2. How do cube roots of non-perfect cubes behave?
  3. Why is a repeating decimal considered a rational number?
  4. How do you determine if a square root will be rational?
  5. What are some common methods for simplifying radical expressions?

Tip: Repeating decimals can always be expressed as fractions, making them rational numbers!

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Math Problem Analysis

Mathematical Concepts

Rational Numbers
Irrational Numbers
Square Roots
Cube Roots

Formulas

√x (Square Root)
∛x (Cube Root)

Theorems

Rational Number Definition
Properties of Repeating Decimals

Suitable Grade Level

Grades 7-10