How Do You Set Up a Proportion from a Word Problem?

A proportion is an equality of two ratios
A ratio is a comparison of numbers by division
'h' is a variable that represents the actual height of the house
Our first ratio is the scale of the blueprint: 2 in over 5 ft
Our second ratio is what we know about the house: 8.5 inches on the blueprint over h feet in real life
Setting the two ratios equal to each other gives us a proportion
Rewrite without labels to give the final proportion

1. 'h' is a variable that represents the actual height of the house
1. This means that every 5 feet of actual house is represented by 2 inches on the blueprint
1. A ratio is a comparison of numbers by division
1. If we can find another ratio, we can set up a proportion for our problem
1. 'h' is a variable that represents the actual height of the house
1. 8.5 inches is the height of the house on the blueprint
2. h feet is the height of the actual house
1. Both of our ratios have inches over feet
2. And both ratios have blueprint length over actual length
1. Since both of our ratios are describing the same thing, we can set them equal to each other
2. This gives us a proportion
3. A proportion is just an equality of two ratios, like we have here
1. Since we don't use labels when we're doing math, we need to rewrite our proportion without them
2. Then we would be able to solve the proportion for our variable, h

The scale on the blueprint for the height of a house is 2 inches for 5 feet. If the roof is 8.5 inches on the blueprint, write a proportion for the height of the house.