I can use proportions to solve problems involving scale.

 Ratio that compares the length in a drawing or model to the corresponding length of the actual object.  A scale drawing is an enlarged or reduced drawing of an object that is proportional to the size of the actual object

 The actual length of a boxcar is 609 in. What is the scale of the model shown?  Write a ratio  Write in simplest form

 You want to make a scale model of a sailboat that is 51 ft long and 48 ft tall. You plan to make the model 17 in long. Explain how you would find the height of the model and give the answer.

 ALL  P.160 # 7-15, 23