357/100
because .57 is the same as 57 hundriths which translates to 57/100. Now you have 3 and 57/100 and to make thing into an improper fraction you follow these steps.
1. mulitply the whole number (the number in front on the fraction) by the denominator (the lower part of the fraction). In our case, multiply 3 and 100. You get 300.
2. Add your answer to the numorator (the upper part on the fraction). 300 plus 57 equals 357.
3. Use your answer as the new numorator and keep the original denomanator.
Answer: 357/100