Fraction From Repeating Decimal
1. **Stating the problem:** Convert the repeating decimal $0.7\overline{5241}$ (where "5241" repeats indefinitely) into a fraction.
2. **Represent the decimal as a variable:** Let $x = 0.7\overline{5241}$.
3. **Separate the decimal into non-repeating and repeating parts:**
The non-repeating part after the decimal is 7 in the tenths place.
The repeating part is "5241" starting from the hundredths place.
4. **Express $x$ in terms of non-repeating and repeating parts:**
$$x = 0.7 + 0.0\overline{5241}$$
5. **Convert the non-repeating decimal:**
$$0.7 = \frac{7}{10}$$
6. **Let $y = 0.0\overline{5241}$ and convert it:**
Multiply $y$ by $10^4 = 10000$ because "5241" has 4 digits:
$$10000y = 5.2415241...$$
Also note:
$$y = 0.052415241...$$
7. **Subtract to eliminate repeating part:**
$$10000y - y = 5.2415241... - 0.052415241...$$
$$9999y = 5.1891099...$$
Correcting this approach to directly convert $0.0\overline{5241}$:
Since $y$ starts at the hundredths place, multiply $y$ by $10^4 = 10000$:
$$10000y = 524.15241524...$$
And to isolate the repeat:
$$10000y - y = 524.15241524... - 0.05241524... = 524.1$$
So:
$$9999y = 524.1$$
8. **Convert to fraction:**
$$y = \frac{524.1}{9999} = \frac{5241}{99990}$$ (multiplied numerator and denominator by 10 to clear decimal)
9. **Combine parts:**
$$x = \frac{7}{10} + \frac{5241}{99990}$$
Find common denominator $99990$:
$$x = \frac{7 \times 9999}{99990} + \frac{5241}{99990} = \frac{69993 + 5241}{99990} = \frac{75234}{99990}$$
10. **Simplify the fraction:**
Both numerator and denominator are divisible by 6:
$$\frac{75234}{99990} = \frac{12539}{16665}$$
No further simplification possible.
**Final Answer:**
$$0.7\overline{5241} = \frac{12539}{16665}$$