This lesson is optional. In this lesson, students apply what they have learned about scale drawings to solve problems involving constant speed (MP1, MP2). Students are given a map with scale as well as a starting and ending point. In addition, either they are given the time the trip takes and are asked to estimate the speed, or they are given the speed and asked to estimate how long the trip takes. In both cases, they need to make strategic use of the map and scale, and they will need to estimate distances because the roads are not straight.

This lesson builds on grade 6 work involving travel at a constant speed. For example, if a car travels at 30 mph, there is a ratio between the time of travel and the distance traveled. This can be represented in a ratio table, or on a graph, or with an equation. If is the distance traveled in miles, and is the amount of time in hours, then traveling at 30 mph can be represented by the equation . Students may or may not use this representation as they work on the activities in this lesson. The work in this lesson can help prepare students for studying proportional relationships in a later unit.