In the attached file, which is a screenshot, I can't get a distance in dimension instead of the 180° angle between the two points. Even when selecting vertical or horizontal sizing... etc.
If anyone could help me, knowing that this is a tutorial file, I would be grateful.
Selecting the 180° dimension, take a look at the value with several decimal places... Maybe the angle is not flat!
If your goal is to dimension the distance between the centers of the 2 arcs of circles visible in the image, try by selecting the 2 arcs of circles (check the "arc conditions" in the attachment line tab of the dimensioning window -> Center to Center).
Try deleting your dimension and recreating it, but selecting the horizontal segment of the center axis. You should get the vertical distance between the two centers
For my part, I would also set the dimension by selecting the arc of the circle, and precisely not the center mark. Normally, it should directly switch to "center-to-center" mode.
A technique that is not very clean but effective: put two sketch points on the entities to be dimensioned. Then use these two points to generate the odds.