Convert 0.72¯¯¯¯¯ to a rational number in simplest form.

3 answers

Let \( x = 0.72\overline{72} \), which means the decimal repeats indefinitely as \( 0.727272...\).

To eliminate the repeating decimal, we can express \( x \) in terms of an equation. First, we multiply \( x \) by 100 (since the repeating part has two digits):

\[ 100x = 72.727272... \]

Now we write the original \( x \) under this new equation:

\[ x = 0.727272... \]

Next, we will subtract the second equation from the first:

\[ 100x - x = 72.727272... - 0.727272... \]

This gives us:

\[ 99x = 72 \]

Now, we solve for \( x \):

\[ x = \frac{72}{99} \]

Next, we simplify this fraction. To do so, we find the greatest common divisor (GCD) of 72 and 99. The prime factorization of each number is:

  • \( 72 = 2^3 \times 3^2 \)
  • \( 99 = 3^2 \times 11 \)

The GCD is \( 9 \) (since \( 3^2 \) is the common factor).

Now we divide both the numerator and the denominator by the GCD:

\[ \frac{72 \div 9}{99 \div 9} = \frac{8}{11} \]

Therefore, the rational number in simplest form that corresponds to \( 0.72\overline{72} \) is:

\[ \boxed{\frac{8}{11}} \]

so the answer is 8/11?

Yes, that's correct! The repeating decimal \( 0.72\overline{72} \) can be expressed as the rational number \( \frac{8}{11} \) in simplest form.