How to make arrow setting in UG NX 7.5
This is what you need to do. In drafting first go to the Annotation toolbar and click on Offset center point symbol. Here you can play with the positon of the center point of the arc. In the offset center point symbol window in the offset option select Vertical Distance from from arc. Choose a distance and select the arc you want to dimension and click OK / Apply. This will create a new center point. You can see this by the + mark on your screen. Now go to dimension toolbar and select Folded Radius Dimension. Select the arc you want to dimension and select the new center point (+) now click in a space between the arc and the new center point.
Answered with a tutorial: https://grabcad.com/tutorials/how-to-make-arrow-setting-in-ug-nx-7-5
You have to create a folded radius dimension first before you can edit it using the dialogue your showing there.
To create a folded radius dimension in Drafting go to 'Insert > Dimension > Folded Radius...' after creating the dimension you can then edit the style with the settings you're showing in your image.