What is the fraction form of the following decimal expansion? 4.372372372372372732...

1 answer

To convert the decimal \( 4.372372372372372732... \) into a fraction, we can break it down into a whole part and a repeating part.

  1. Separate the whole part and the repeating decimal:

    • The whole number part is \( 4 \).
    • The decimal part is \( 0.372372372372... \).
  2. Let \( x = 0.372372372372... \):

    • This can be expressed as follows: \[ x = 0.372372372372... \]
  3. Multiply \( x \) by \( 1000 \) to shift the decimal point three places to the right: \[ 1000x = 372.372372372372... \]

  4. Now, subtract \( x \) from \( 1000x \): \[ 1000x - x = 372.372372372372... - 0.372372372372... \] \[ 999x = 372 \]

  5. Solve for \( x \): \[ x = \frac{372}{999} \]

  6. Simplify the fraction \( \frac{372}{999} \):

    • The greatest common divisor (GCD) of \( 372 \) and \( 999 \) is \( 9 \).
    • Dividing both the numerator and the denominator by \( 9 \): \[ \frac{372 \div 9}{999 \div 9} = \frac{41.3333...}{111} \] This simplifying shows that \( 372/999 \) reduces to \( 41/111 \).
  7. Now, combine the whole number part with the fractional part:

    • Therefore, the full number is: \[ 4 + \frac{41}{111} = \frac{4 \times 111 + 41}{111} = \frac{444 + 41}{111} = \frac{485}{111} \]

Thus, the decimal \( 4.372372372372372732... \) can be expressed in fractional form as:

\[ \boxed{\frac{485}{111}} \]