Use the Measure Units/Precision dialog box to modify units of measure used by the Measure tool.
To modify units of measure:
Click Units/Precision
in the Measure dialog
box, select from the following options, then click OK.
Use document settings. Select to use the units and material properties defined in Document Properties. To access Document Properties, click Tools, Options, then on the Document Properties tab, select Units and Material Properties.
Use custom settings. Select to change the following:
Select a unit of measure for linear dimensions. If you select Microinches, Mils, Inches, or Feet & Inches, then also select from the following:
Decimal.
Fractions. If you select Fractions, then also select from the following:
Denominator. Set the denominator. For example, set to 8 to report values in increments no smaller than 1/8 inch.
Round to nearest fraction. Select to round values to the nearest fractional increment set in Denominator. Clear to report values as decimals if the fractional increment is smaller than that set in Denominator.
Scientific Notation. Select to display values in scientific notation (for example, 5.02e+004 for 50200).
Decimal places. Set number of decimal places to display for linear dimensions.
Select a unit of measure for angular dimensions. If you select Degrees or Radians, then also set:
Decimal places. Set number of decimal places to display for angular dimensions.