It is given that Sonia takes 4/5 mile walk everyday.
Consider 4/5 represent the 100%
so using the proportion we can determine which part of her walk she completed once she has walked 3/5 miles.
Find out what percentage represent 3/5
Let
x -----> the percentage that represent 3/5
Then convert to fraction number



Therefore , the value of x in percentage is 75 percent.
Convert into fraction number.

Hence , she has completed 3/4 of her walk once she has walked 3/5 miles.