Question

Design for a library has a scale of 1/3 inch equals 1 foot. The height of library in the drawing is 12 inches. Whats the actual height of the library?

Answer 1

So we know 1/3 of an inch is the same as 1 foot. Which is 12 inches.

So it's easier to calculate, we can say that 1/3*3 = 1. Therefore, we don't have to deal with fractions.

This means that we need to multiply 3 * 12 = 36 to find out how many 1/3's we need. So multiply 1/3 by 36 to double-check:

1/3 * 36 = 12.

The question is asking us the actual height. And we know 1 foot = 1/3 inches.

1 * 36 = 36 feet.

Another way to do it is, we know that there are 3    1/3's  to get to 1. Which means it's 3 feet IRL. We know we gotta multiply by 12 to get to 12, so

3*12 = 36.