Math Problem Statement

Show that the following number is rational by writing it as a ratio of two integers. 0.747474... (repeating decimal)

Solution

The problem in the image asks to show that the number 0.747474... (a repeating decimal) is rational by writing it as a ratio of two integers.

Solution:

To express 0.7474740.747474\ldots (repeating) as a fraction:

  1. Let x=0.74747474x = 0.74747474\ldots.

  2. Multiply both sides by 100 to shift the decimal two places to the right: 100x=74.74747474100x = 74.74747474\ldots

  3. Now subtract the original equation x=0.747474x = 0.747474\ldots from this new equation: 100xx=74.7474740.747474100x - x = 74.747474\ldots - 0.747474\ldots This simplifies to: 99x=7499x = 74

  4. Solve for xx: x=7499x = \frac{74}{99}

Thus, 0.747474=74990.747474\ldots = \frac{74}{99}, showing that it is a rational number.

This matches the answer shown in the image, which is 7499\frac{74}{99}.


Do you have any questions or would you like more details on this solution?

Here are 5 related questions for further exploration:

  1. How can you convert a non-repeating decimal to a fraction?
  2. What is the general method for converting repeating decimals into fractions?
  3. Can every repeating decimal be expressed as a fraction?
  4. What is the difference between a rational and an irrational number?
  5. How can you simplify fractions derived from repeating decimals?

Tip: When converting repeating decimals to fractions, always try multiplying by powers of 10 to eliminate the repeating part during subtraction.

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Math Problem Analysis

Mathematical Concepts

Rational Numbers
Repeating Decimals
Algebra

Formulas

x = 0.747474...
100x = 74.747474...
100x - x = 99x
x = 74/99

Theorems

Repeating decimals can be expressed as fractions

Suitable Grade Level

Grades 7-9