Center Lines on a Slot for Dimension Creation in Inventor

dimension a slot   Dan dimensioning a slot

For Wildfire 4 and lower , select Axis Point from the top Sketch menu In Wildfire 5 or later , you add a Geometry Point

The tight key is a connection component fitting into the slot of the shaft and in the hub with torque being transmitted only by the sides of keys The key slots Showing how to Dimension Tangentially and Arc Slots with Autodesk Inventor

kimochi slot The dimensions of the entire cylindrical slot are: = inches, = inches and length = inches  For the slot, I would just like to know how to dimension the length of the slot When I select the two cylindrical ends, the dimension goes to