The Center Radius measurement tool places specialized markups that calculate the radius a circle based on the position of the circle's center and one point on its circumference.
As with any measurement, be sure to calibrate the document first.
Select a markup to reveal its control handles. Each handle controls a different aspect of the markup's size and orientation.
To rotate the markup, click and drag the orange handle outside the markup (when the markup is first placed, it will be at the top). By default, the markup is rotated in increments of 15°; to rotate in increments of 1°, hold down SHIFT while dragging.
The rotation can also be entered in the Rotation field found in the Layout section of the Properties tab.
To rotate the caption, click and drag the orange handle directly over it. By default, the markup is rotated in increments of 15°; to rotate in increments of 1°, hold down SHIFT while dragging.To return a rotated caption to its original position, right-click it and select Reset Caption Position.
To change the size of the arc, click and drag one of the yellow handles on the markup's circumference.
To change the length of the radius, click and drag the yellow handle at the circle's center.
To move the entire markup together, click and drag a part of it other than the control handles.
To scale the markup up or down, click and drag the appropriate purple handle.
See Editing Markups for more information.
The appearance of the Radius measurement is configurable, including line and fill color, line width and style, opacity, plus the font style of the caption and whether or not to show it.
To change the appearance of a Radius measurement, select it and click the Properties tab.
Color: Sets the line color.
Fill Color: Sets a fill color.
Highlight: Makes the fill color and/or hatch pattern transparent so underlying content shows through.
Opacity: Sets the line opacity, from 0 (invisible) to 100 (opaque).
Fill Opacity: Sets the fill opacity, from 0 (invisible) to 100 (opaque).
Line Width: Sets the thickness (in points) of the line. A setting of 0 effectively renders the line invisible.
Style: Determines the line pattern.
Show Caption: Select to include the caption text on the markup.
Show All Measurements: Select to include all measurements applicable to the markup, not just the default measurement.
Font Size: Sets the size of the font.
Text Color: Sets the color of text.
Font Style: These settings control the formatting of the text. Options include Bold, Italic, Underline, and Strikethrough. Generally, any combination of these styles can be applied to format the text.