Dear Friends, I am a new subscriber, and I would like to ask for your assistance regarding a simple VBA program: I would like to know how to write the VBA algorithm for the following program : Computing Clockwise Rotation Determining if a point is to the left or right of a line One effective computational geometry task is to determine if a point is located clockwise from a straight line. This is useful to determine if a point is inside a polygon, or if a house is located on a particular side of the street. Given a straight line segment, and an individual point as defined below: Line := (10,10) (50,50) Point := (25,26) The cross product of the line matrix can be computed through standard arithmetic. If the sign of the cross product is positive, then the directed segment p1pn is clockwise from p1p2. Crossprod:=(point0-line0,0).[line1,1-line0,1]-(line1,0-line0,0).(point1-line0,1) Crossprod=-40 I am looking forward your assistance at your soonest convenience