In the context of slope calculations, what do VD and HD stand for?

• A. VD = vertical distance; HD = horizontal distance
• B. VD = velocity distance; HD = height distance
• C. VD = visible distance; HD = horizontal direction
• D. VD = vertical diameter; HD = horizontal diameter

Answer: (A)

In slope calculations, you’re looking at how much you rise versus how far you move horizontally. VD stands for vertical distance, the change in elevation (the rise). HD stands for horizontal distance, the distance you move along the ground (the run). The slope or grade is found by dividing the vertical distance by the horizontal distance.

The other terms don’t fit because they describe things not used in standard slope work: velocity distance isn’t a conventional term for slope, height distance isn’t the usual pair with horizontal distance in this context, and visible distance or horizontal/vertical diameters refer to different concepts altogether.