A plane has an altitude of 23760 feet which expression can I use to find the altitude in miles

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