Special Dimensions

The first of these methods require knowing the correct order and geometry to select to the get the dimension you’re looking for.  I will go over each in detail, and also show the order in which you need to pick the geometry with the Dimension Tool.
Arc Length Dimension

To get the length of an Arc in SOLIDWORKS using Smart Dimension, you need to first select the two end points (1), then select the arc itself (2).  Once you’ve done this you will be presented with a preview of the dimension (3), which you can then place and specify the desired length.  It’s worth mentioning that this dimension by default is a driving dimension.  However, you can add this dimension also as a reference dimension if you only want to see the value.

Angle Dimension without Construction Geometry

The next dimension allows you to create an angle between two endpoints of an arc without the need to create any Construction Lines.  Typically, users spend the extra time to draw Construction Lines from the center of the arc, and then place angular dimensions on those.  To create this dimension, first, like before select the two endpoints (1).  This time however, select the center of the arc (2).  Like before, you will be presented with a preview of the dimension, in this case an angle (3), which again, you can place and use as either a driving or driven dimension.

Angle Mates without Construction Geometry for Lines

Finally, the last type of mate is another Angle Mate, this time specifically for Lines.  Like before, often times you need to have some form of reference or construction geometry available to reference.  However, in SOLIDWORKS 2015, there’s a new way to create these dimensions, and very flexible in how it works.  First, you need to select the line you want to apply the angle to (1).  Then, select one end point of the line (2).  As soon as you do this, SOLIDWORKS will now present you with a reference Compass in which you need to specify which polar direction you want to apply the angle to (3).  Once you do this, like the other two examples, SOLIDWORKS will present you with a preview of the dimension, and you only need to place it (4).  And of course like the other two examples, this dimension is driving by default.