It's very easy. Just provide 2 vectors calculated from your 3 points. Assuming they are like this:

then (B-A) for the first input, (C-A) for the second input.
halfdanpusat
When you type into this search field and press Enter, I think it only makes sense to trigger Find because there is nothing else to do. Right now pressing Enter only loses focus from the textbox, and requires you to click Find.
I would prefer it to be search-as-you-type