[MR] Dayshade Mathematics

[Gorm of Berra]

Unto the assembled geniuses does Gorm of Berra send greetings:

So, as a result of one of those attacks of helium-handedness (aren't 
scientists working on a vaccine yet?), my lovely Lady and I are 
spearheading a project to build a 10x14 dayshade for the local Barony.

I *believe* I have figured out the mathematics necessary to make a bunch of 
canvas turn into what we're looking for, but would appreciate it if someone 
could double-check.

Basically, we're looking for a 10x14 dayshade, with a 7' wide and 8' tall 
ridgepole in the middle, and the edge poles being 6' (meaning a peak height 
of 2').

My sketches (which seem to work with a paper mockup) say that we will need 
the following pieces:

1.  2 @ 3'6" wide x 11' long (all pieces need seam allowances added, of 
course) for the center section of the long side.

2.  4 @ A right triangle with base 3'6" and height 5'6" (leaving hypotenuse 
of 6' 7")

3.  2 @  isoceles triangles with base of 10' and sides of 6'7" (matching 
the hypotenuse from the others)

Is this about right?  Am I shorting myself somewhere (aside from seam 
allowances and dags, which get added later)?  Is a 2' peak height sufficient?

Gorm