Nope.... You need to draw the construction line.
If this is important to you be sure to put in an Enhancement Request on the SolidWorks Customer Portal.
I guessed that was the answer but hoped that someone knew how it could be done.
Deffo requires an ER
How does the reader know that your construction line is vertical?
Additionally, the 5 degree dimension constrains your block against rotation. This may bite you in the bum later on.
You could dimension the internal angle as 85 degrees, and add a text note "Draft 5 degrees".
I recommend always explicitly stating the designer's intent, rather than expecting the reader to infer it from obscure dimensions.
Without an understanding of design intent, people working on this job after you may stuff it up.
The ASME Y14.5 standard states that all lines that appear horizontal or vertical shall be interpreted as being precisely so, without requiring it be labeled so. I think this covers the case Colin shows.