Making perpendicular lines to existing line features in ArcPy with ArcGIS Pro

Question

I have reviewed and tried multiple different answers to similar questions but have not got the results expected. I have a layer with 4425 polyline features and want to make a perpendicular line feature for every existing line that is in a specific layer that will go from the centerpoint of the current line features and intersect through other line features. The black arrow is an example of the output, red is the layer I am getting the midpoint from, and blue is the layer I want the perpendicular lines to intersect. My current code is:

cursor = arcpy.SearchCursor("SpatialJoinLayer")
features = []
distance = 10
for row in cursor:
   #Get midpoint of line feature
   midpoint = row.shape.positionAlongLine(0.5, True).firstPoint
   angle = row.Angle
   startX = midpoint.X
   startY = midpoint.Y
   #Formula that I believe is wrong but cannot figure out where the problem is
   endX = distance * math.cos(angle) + startX
   endY = distance * math.sin(angle) + startY
   arr = arcpy.Array([arcpy.Point(startX, startY), arcpy.Point(endX, endY)])
   polyline = arcpy.Polyline(arr)
   features.append(polyline)
#Add a feature class and add the newly created lines to it
arcpy.management.CreateFeatureclass(arcpy.env.workspace, "PerpLines")
arcpy.management.CopyFeatures(features, "PerpLines")

Answer 1

The error is just a geometry issue: you need to modify it as follows:

...
# need 90deg in order to find perpendicular
pi_by_2 = math.pi / 2.0

# now add that value to the row's angle
angle = row.angle + pi_by_2
...

Also, as commented by another user, please add an SRID to the geometry when using the arcpy.Polyline geometry factory to create the feature!