code: def strike2dip_direction(strike):
      
      strike = parse_azimuth(strike)
      dip_direction = strike + 90
      if dip_direction > 360:
          dip_direction -= 360
      return dip_direction
docs: Converts a planar measurement of strike using the right-hand-rule into the
      dip direction (i.e. the direction that the plane dips).
  
      Parameters
      ----------
      strike : number or string
          The strike direction of the plane in degrees. This can be either a
          numerical azimuth in the 0-360 range or a string representing a quadrant
          measurement (e.g. N30W).
  
      Returns
      -------
      azimuth : number
          The dip direction of the plane in degrees (0-360).