Neural Network type conversion problem

So Im basically trying to make a neural network that tells if a defined set of points (vector2s) are in a line. The thing is that I want to end the output with a confidence of how “liny” it is and my first node is a list of vector2. How can I start with vector2 and end in a float? Or is there a logical way to convert a v2 to a float?

While you could possibly do this with an ANN, you could also search for a C# Linear Algebra or Statistics library and use linear regressions to solve this with considerably less time and effort.