How to calculate the true thickness of a layer from the geologic map with given apparent thickness and angle of dip?

We have four laws:

True thickness= outcrop width *sin (dip angle+  Angleregression)

(If the dip angel is opposite for slope of earth).

True thickness= outcrop width*sin (dip angel- Angleregression)

(If the dip angel is  same side  with slop of earth)

True thickness= outcrop width*sin (Angleregression)

(If the horizontal layers and surface of earth is regression)

True thickness= outcrop width*sin (dip angel)

(If dip layers and surface is horizontal)