To express the fraction \(\frac{25}{32}\) as a decimal fraction rounded to 4 decimal places, follow these steps:
1. Divide the numerator by the denominator: Perform the division \(\frac{25}{32}\) to convert the fraction to a decimal form.
2. Determine the Resulting Decimal: After performing the division, we get a decimal number.
3. Round the Decimal: Round the resulting decimal to 4 decimal places to match the precision required in the question.
From the computation, the resulting decimal is approximately \(0.7812\).
Therefore, \(\frac{25}{32}\) expressed as a decimal fraction rounded to 4 decimal places is:
[tex]\[
\boxed{0.7812}
\][/tex]
So, the correct answer is:
[tex]\[
\text{b. } 0.7812
\][/tex]
