Where is 0.8125 on the ruler shown?

To locate 0.8125 on a ruler, first understand that it is equivalent to 13/16 inches. On a standard ruler, this would be just slightly before the 7/8 inch mark, as 7/8 is 0.875. You can divide the space between 0.75 and 0.875 into four equal parts, and 0.8125 will be the third mark from 0.75.