These dividers will scale up or down with a high degree of accuracy. You could use a ruler and a calculator to work it out, but proportional dividers will do it for you automatically. By adjusting the joint, you can set the tool to any transfer ratio from 1:1 to 1:10. The distance between points at one end is in the chosen ratio to the points at the opposite end. The dividers have other functions. They will divide the circumference into equal segments, from 6 to 15. Using the GS mark gives the ratio of 1:1.618 hence GS for Golden Section. The mark Square Root 2, gives the length of the hypotenuse of a right angle triangle with two equal sides, or 1:1.414. This is an invaluable tool for transferring scale. Use for drafting, technical drawing and chart making. It has a passivated-chrome finish with stainless steel points. The overall length is 185mm.