You can measure the radius of a circle or arc in the viewport. The measurable drawing elements can be any of the following: view and added geometry, center and symmetry lines, sketches, and the sheet frame.
To measure a radius,
1. Click Annotation, Geometry, or Insert and then, in the Utilities group, click the arrow next to .
2. Click Radius. The Measure dialog box opens with the Radius Output box.
3. Select a circular element in the viewport to measure.
The element's radius is displayed in the Radius Output box.
4. Continue selecting elements, or click (Apply) or Cancel to complete the command.
You can click (Apply) to use the output from Measure as input for an interrupted operation.
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Radius. The Measure dialog box opens with the Radius Output box.
(Apply) or Cancel to complete the command.