Nautical Miles

A nautical mile equals the length of arc subtended by a central angle of 1 minute on a "great circle" on the surface of the Earth. If the radius of the Earth is taken as 3960 miles, express 1 nautical mile in terms of ordinary, or statute, miles.

A great circle, according to the book, is "any circle drawn on the surface of Earth that divides Earth into two equal hemispheres."

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Originally Posted by magentarita

A nautical mile equals the length of arc subtended by a central angle of 1 minute on a "great circle" on the surface of the Earth. If the radius of the Earth is taken as 3960 miles, express 1 nautical mile in terms of ordinary, or statute, miles.

A great circle, according to the book, is "any circle drawn on the surface of Earth that divides Earth into two equal hemispheres."

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If R = 3960 statute miles. then one great circle is 2pi(3960) statute miles.
That is for 360 degrees.
In minutes, that is 360*60 minutes
So, 1-minute central angle will subtend
(2pi*3960 statute miles) / (360*60 min)
= 1.15192 statute miles per min.

Therefore, 1 nautical mile = 1.15192 statute miles -------answer.

I could have never worked that question out myself.

Can you help me with the other question about sunrise?