Sarah has built a scale model of a bridge. The real bridge is 56 ft across and 21 ft wide. Sarah's model is 8 in. across and 2.5 in. wide. Is Sarah's model a true model of the bridge? Explain.

To determine if the model is a true model. Solve for the scaling used for both the measurement across and the width. The scaling of both should be the same.

(across) 56 ft / 8 in = 7 ft per 1 inch

(width) 21 ft / 2.5 in = 8.4 ft per 1 inch

Since, the scalings are not the same then, Sarah's model is not a true model of the bridge.