Lines have one dimension, polygons have two dimensions, solids have three dimensions. Lines only have the dimension length. Polygons have the dimensions length and width. Solids have the dimensions length, width, and height.
Stefano is at +10 elevation while the hiker is at -166.4 elevation. The difference would be 10 - (-166.4) = 10 + 166.4 = 176.4 or approximately 176 meters
