Brass 9 Inch. Proportional Divider Steel End For Sharp Point This detailed item measures approximately 9 inches Point To Point and 3/4 inch wide. Among several functions, proportional dividers can be used to increase or decrease lengths of lines and diameters of circles, and can they be used to inscribe regular polygons within circles (dividing the circumference of a circle into equal parts). Fine piece of drafting equipment-very well made. NOTE: No guarantee on the accuracy, as this depends on the person using the item. ( for example if you do not have short end set at exactly 1 in and the long end set at 3 in you will not have a 3 in to 1 in ratio