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Use the Units panel of the Document Setup dialog box to configure the units used for lengths in LayOut. The units format applies to Measurements and the Paper size settings.
Select Fractional or Decimal from the first Format drop-down list. Select the unit type from the second Format drop-down list.
Click on the 'Precision' drop-down menu to set the precision for displaying units. Fractional unit precision can be set from 1" to 1/64". Decimal unit precision can be set in numbers of decimal places beyond zero for any of these units. LayOut users working in Metric should use the decimal unit setting.