Lookup price with two parameters

Hello guys, I confess that I absolutely suck at both math and excel. Unfortunately my boss handed me what is basically a math problem I gotta solve, and I have no idea how to do it cause of lack of my math and excel skills. I am hoping someone can help me with this or I'm screwed.

Co basically I've got this table in excel, where X (row) is a width and Y is a height (column) of a wooden sauna cabin, the X;Y is the price for a sauna with said dimensions. I need to find a relationship between the size and the price. I can't seem to find it, the price seems to grow non linearly, I can't seem to find any coeficient. Again, I suck at math and excel, maybe solution is simple, but I just don't see it. Can anyone help me please?

Table is at this link - ibb.co/4WsJ07h . Thanks for any help!