Dimensioning a Drawing - AutoCAD 2011 and AutoCAD LT 2011: No Experience Required - page 627

By default, the values in the Child Dimension Style dialog box will
be the same as the values found in its parent. For instance, switching
to the Symbols and Arrows tab will reveal that the Arrowhead setting
is Architectural Tick, the same as the parent A-DIMS-PLAN style.
4. From the Symbols and Arrows tab, click the Second drop-down list
within the Arrowheads group to change from Architectural Tick to
Closed Filled, as shown in Figure 12.36.
FiGuRE 12.36 Changing the Arrowhead style for the
Radial A-DIMS-PLAN child style
The change you just made will not affect the way you actually cre-
ate dimensions. You'll still use the A-DIMS-PLAN dimension style.
The only difference is that when you create a radius dimension, it
will use a filled arrow instead of the architectural tick that was used
when creating a radius dimension earlier.
5. Click OK to close the New Dimension Style dialog box.
6. In the Dimension Style Manager dialog box, notice the Styles list; as
shown in Figure 12.37, the current dimension style now has a child
style for Radial dimensions indented below it.