> Kitas variantas kaip suprantu naudoti keystone (pagal 
> http://stephenmason.com/misc/projectorkeystone.html) būtų 5% - tik 
> nelabai įsivaizduoju čia daug ar mažai?

o cia nebus pitagotinis statiniu santykis?

http://projectors-av.co.uk/keystone_lens_shift.html

Keystone correction is expressed in degrees and
shows the angle that can be corrected digitally.

http://researchmaniacs.com/Math/Tangent/Degrees/What-is-Tan-5-Degrees.html

Opposite = 0.087 x Adjacent
Opposite = 0.087 x 430 = 37,41 cm