Posted by Nick on .
A certain car is about 100in. long and 60 in. wide. You plan to make a model of this car that is 9 in. wide. How long will your model be?

Math 
Reiny,
60 inches : 9 inches
= 20:3 , is your ratio or your scale
so just set up a simple proportion
x/100 = 9/60
x = 100(9/60) = 15
it should be 15 inches long
notice: 100/15 = 20/3
and 60/9 = 20/3