The span of the benjamin franklin suspension bridge in philadelphia, pennsylvania, is 1750 feet. a model of the bridge has a span of 42 inches. what is the scale factor of the model to the span of the actual benjamin franklin bridge?

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.