Final answer:
Isabella will have 2.02 yards of fabric left over.
Step-by-step explanation:
To find out how much fabric Isabella will have left over, we need to subtract the total length she needs for her costume (three 4.2-yard pieces) from the amount of fabric she purchased (14.62 yards).
First, we calculate the total length needed for the costume: 4.2 yards x 3 = 12.6 yards.
Then, we subtract the total length needed from the amount of fabric purchased: 14.62 yards - 12.6 yards = 2.02 yards.
Therefore, Isabella will have 2.02 yards of fabric left over.