Thread: homework question...pythag th i think

Assume the earth is a perfectly round sphere with a radius of 4000 miles and that 1 mile=5280 feet. How far does the horizon appear to be to a 5-ft person on a clear day? Explain.


i thought the answer would be just a small fraction over 4000 miles, so essentially the height of the man does not change how far the horizon appears to the man.

am i on the right track here?

Originally Posted by igottaquestion

Assume the earth is a perfectly round sphere with a radius of 4000 miles and that 1 mile=5280 feet. How far does the horizon appear to be to a 5-ft person on a clear day? Explain.


i thought the answer would be just a small fraction over 4000 miles, so essentially the height of the man does not change how far the horizon appears to the man.

am i on the right track here?

You are dealing with a right triangle. (See attachment)

The distance from the eye of the observer to the horizon is calculated according to Pythagorean theorem:



Solve for d

Spoiler:

I've got . If you want to increase the radius of the field of observation you should climb a hill or use a lighthouse.