Originally Posted by

**prevaricator** I'm trying to make a model in excel which calculates the dip angle

and direction (azimuth or bearing) of a plane descriped by 3 points in a coordinate

system.

The planned use is a quick-look geomodel where I would like to

calculate formation dip based on the observation of a specific

geological feature in three separate wells. The points where the

well intersects the formation in each well is described by a UTM

latitude/longitude and depth below a fixed datum. Point 1 (x1, y1,

z1), point 2 (x2, y2, z2), point 3 (x3,y3, z3).

By definition, the dip angle is perpendicular to the strike (a

horizontal line through the plane) 0 degrees meaning a horizontal

plane/90 degrees meaning a vertical plane, and the dip azimuth is

the compass direction/bearing of the dip angle.