** Known** **values:**

**Solution:** Elevation of point X, ** H_{X}**.

The road has a constant grade** S** along the examined section, which equals to tangent angle

**, formed by the tangent AB and the horizontal plane.**

*Î±*Grade ** S** calculation:

Elevation of point X, HX. The road has a constant grade S along the examined section, which equals to tangent angle Î±, formed by the tangent AB and the horizontal plane.

Grade S calculation: