Obtaining the point at a certain percentage along a line segment

I have a method that returns the mid point of a line segment as defined by two points; ``` public static PointF GetMidPoint(PointF p1, PointF p2) { return new PointF((p1.X + p2.X) / 2, (p1.Y + p2.Y) / 2); } ``` Which works exactly as expected. However, I now need to find an arbitrary percentage along the segment (say, 35%), which in principle should(?) be as easy as; ``` public static PointF GetArbitaryPoint(PointF p1, PointF p2, double percentage) { return new PointF((p1.X + p2.X) / percentage, (p1.Y + p2.Y) / percentage); } ``` But that doesn't seem to be the case, I think it's a c# issue - as soon as you introduce a decimal point (whether it be a Point or a PointF) it throws it's toys out of the pram and returns bizarre results. So I suppose the question is how would I modify the above to get it do what I need? Thanks in advance.