Proportional scale makes changing dimensions easy
Changing the size of a project leads to cumbersome math at times. Say you're enlarging a piece that's 3⁄8 " wide and 6" to 8" long. How wide should it be?
A graphic artist's proportional scale makes such calculations simple. You just set the original dimension on the rotating circular scale next to the new measurement. Then, each new dimension will be shown right next to the corresponding original. You can set the wheel to a known percentage of enlargement or reduction, too, to determine new measurements. And, it shows you the answers in fractions of an inch, not decimals. (Ours covers a range from 1⁄4 " to 90".) You can buy one at an art-supply store. By the way, you need to make that piece in our example 1⁄2 " wide.
—Bill Kuhlmann, Colorado Springs, Colo.