Explanation
Because the ratio of inches to actual distance is constant, a proportion can be used to solve for the unknown distance. Set up a proportion to represent the situation. The question supplies a ratio of 10 inches to 100 feet and asks for the distance represented by 25 inches. Write a proportion equating the given information with the unknown information, being sure to keep the units of each ratio consistent (all inches on top or all inches on bottom):
\(\frac{10in}{100ft}=\frac{25in}{xft}\)
Use cross multiplication to solve for the unknown, x feet, as follows:
10x=25*100
x= 250 ft