Answer:
The percent of increase in the shoreline was 38%.
Explanation:
Given that the shoreline increased from 10 miles to 13.8 miles because of the spring runoff, to determine the percentage by which the shoreline increased, the following calculation must be performed:
10 = 100
13.8 = X
((13.8 x 100) / 10) = X
(1,380 / 10) = X
138 = X
Thus, since 138 - 100 is equal to 38, the percentage by which the shoreline increased was 38%.