2D Linear Interpolation in Excel

Excel doesn’t have a built in function dedicated to linear interpolation. It’s still possible to do it, but it can be cumbersome. Normally, I would just complain and use the tools provided to muddle through, but I came upon a situation where writing a custom function was less work than creating the convoluted monster of standard excel functions required to do what I wanted to do, 2D linear interpolation.  Introducing LInterpolate…