Calculating a value from a collection of given points on the graph?

[Itamar]

Hey. I need a function that does something like this: I give it a collection of (X, Y) points on my graph, plus another X point. Then the output is the Y coordinates in the given X. Something like this:



The blue points are given, and then I give another X value and get it's Y value. I went through a lot of the mathmatics functions and found nothing that performs this action, so it would be really helpful if anyone could help me find the right VI to do this.

thanks,
Itamar.