Final answer:
Fractions 3/7 and 4/9 require adding a decimal point and zero to their dividends before division to convert them to decimals. This is because their denominators, 7 and 9, are not factors of 10 and thus won't divide into an integer without extending the dividend with decimals and zeros.
Step-by-step explanation:
When using long division to convert a fraction to a decimal, fractions where the denominator isn't a factor of 10 would require adding a decimal point and zero to the dividend before dividing. Looking at the given options:
- 3/7 cannot be evenly divided into 3 without adding a decimal and zeros because 7 is not a factor of 10.
- 1/2 does not require adding a decimal and zeros as 2 is a factor of 10 and would divide evenly into 10, resulting in a terminating decimal.
- 2/5 also does not require extra zeros since 5 is a factor of 10.
- 4/9 would require adding a decimal and zero because 9 is not a factor of 10.
In conclusion, fractions a. 3/7 and d. 4/9 would require adding a decimal point and zero to the dividend before dividing to convert them to decimals.