The Martin family is considering building a new house. On the blueprints, the dimensions of the outside of the house are 18 inches wide by 26 inches long. If the house is actually going to be 45 feet wide, what will the actual length of the house be?

This can be answered through simple ratio and proportion

Let x = width

y = height

x/y = x2/y2 = x3/y3

since

for 18 inches width we have 26 inches as length, therefore

18/26 = 45/y2

y2 = 65 ft

there is no need to convert the units for the smaller dimensions since we are dealing with definite ratios thus unitless.