assuming you mean on the earth, not some other planet or polyhedral body,
If d is the distance, and r is the radius of the earth (in feet),
r^2 + d^2 = (r+32000)^2
Find the distance to the horizon @ 32,000 feet.
2 answers
If d is the distance, and r is the radius of the earth (in feet),
r^2 + d^2 = (r+32000)^2
r^2 + d^2 = (r+32000)^2