[TheForge] lamp shade

[Andy Gladish]

Dave, the way I visualise this kind of thing is to take the extreme cases:
in a cubic lampshade, the angle would be simply 90 deg. In a very flattened
out lampshade, the angle pieces would be practically lying on the table,
with their spines sticking up in the air- obviously not making the correct
angle to one another.
But it's embarrassing to go in a short 12 yrs. from doing calculus daily to
being so non-fluent in trig that I just shrug at Janet's question and say, I
also have no idea how to derive the correct angle. (;_*)

Ries- thanks for your ideas and kind offer. I'll try your suggestion and
beat on it and see if it submits to a logical argument in the shape of a
hammer. If not, I get to learn how to use a real brake: win/win in any case!

Andy Gladish
Guemes Island, WA


> I have been waiting for someone to raise this question.  I can't
> see how you
> need anything other than a 90 degree angle for the vertical side
> pieces.  If
> you take a horizontal slice through a truncated pyramid it will
> be a square
> and those angles must total 360 and be 90 each or it isn't a square.  Now
> the included angle of the piece across the bottom will be something less
> than 90 and the angle across the top will be something more than a 90.  I
> would do the top and bottom out of flat stock with tabs welded on
> to hold my
> filler material.  Take a piece of paper and fold it into a 4
> sided payramid,
> the angle of the fold is still a 90.  Or am I missing something?
>
> Dave Smucker


>