Pat has the definition and GLV (hi George) has the measurement for 100 yards.
As Pat indicates a Minute is 1/60th of a degree and we all
Know that a circle has 360 of those.
SO:
360 degrees X 60 minutes per degree equals
21,600 minutes in a circle.
The circumference of a circle equals Pi X Diameter or
3.14 X Diameter
Diameter(equals 2X [the radius for a 100 yard MOA] (100 yards X 36 inches)=
7200 inches)
So.. 3.14 X 7200 = 22608 inches around a circle of 200 yards in diameter.
The circumference of 22608/21600 minutes in a circle =
1.047" subtended by an angle of One minute at a radius of 100 yards.
Hence:
One Minute of Angle = 1.047" at 100 yards
One Minute of angle = 5.233" at 500 yards
One Minute of Angle = 10.47" at 1000 yards
No mystery here, just simple geometry.
Hope this helps!
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Ni ellegimit carborundum esse!
Yours In Marksmanship
http://www.1bigred.com/distinguished
michael