Perhaps we can treat this as a "distance to horizon" problem, the observer is 7 mi above the earth
One formula is: d+=+sqrt%28%283h%29%2F2%29 where d is in miles and h is in feet
Change 7 mi; 5280*7 = 36960 ft
so we have
d = sqrt%28%283960%2A3%29%2F2%29
d ~ 235.5 mi
looking in opposite directions a total of 2*235 = 471 mi can be viewed
Find the circumference of the earth
C = pi%2A8000
C = 25133 mi
:
The arc: 471%2F25133 * 360 = 6.7 degrees
:
This should be pretty close, because the earth is so large compared to the altitude. would appreciate if it you would let me know. C