How can I make this dimension look like this?

[RA_9909671]

When I use the dimension option in the annotations tab the dimension end up been like this (in the red circle): 

but I needed it to be like this (also in the red circle):

How can I do it?

[StephenW · Accepted solution]

Make sure when you select, you are selecting the line and not the vertex (both places). Selecting 2 lines at an angle to each other will yield an angle dimension but if either selection is a point (vertex/endpoint/midpoint), the dimension will be a linear dimension (vertical/horizontal/slanted) based on your placement.

[RA_9909671]

True! Now it worked.
Thanks for the help