 Foresters have generally adopted the engineer scale for measuring distances on maps. A typical engineer scale has six scales arranged on a triangular instrument. If you look at a scale, you will see the numbers 10, 20, and 30 on one end as you rotate. And if you flip to the other end and rotate, you will see 40, 50, and 60. These scales measure in 1-tenths, 1-twentieths, 1-thirtieths, 1-fortieths, 1-fiftieths, and 1-sixtieths of an inch respectively. Using your scale, look at the equivalence of different points along the various sides. On the 10, or 1-tenth of an inch per division scale, each small division is 0.1 inches. A quick way to determine inches is to count the tick marks and then divide by the number printed on the end of the scale. 10, 20, 30, etc. For example, on the 50 side of the scale, the large mark between the 4 and the 6 mark is 5, or 50, 1-fiftieth tick marks, which is 1 inch. Therefore, the 20 mark on the 50 side of the scale is 200 tick marks, or 200 divided by 50 is equal to 4 inches. Using an engineer scale allows for the precise measurement in a decimal format that is not possible with a conventional ruler.