How to calculate length of diagonal lines across rectangle?

Factual Questions
21

This is just the rudimentary planning stage.

Once I actually have the wood (I’m going to build it mainly from 1x12 oak or maple), I’ll measure out, cut, and assemble the interior boards, then build the outer frame around it. I’m not a professional carpenter, so there will probably be a lot of trial-and-error involved even with proper, accurate measurements . :slight_smile:

22

1x12 lumber, I presume? This ehow is exactly how I would go about it: ehow | ehow

23

Yeah that’s pretty much it.