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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Spherical triangles versus plane triangles
From: Frank Reed
Date: 2025 Sep 17, 09:39 -0700
From: Frank Reed
Date: 2025 Sep 17, 09:39 -0700
David Pike, you wrote:
"After sleeping on it, the general case appears not to be that difficult. It's two sides and an included angle."
Yes, I agree. And as you suggest, one could make a nice little spreadsheet to try different cases. For those who "don't do spreadsheets", I suggest trying simple cases: if the 3,4 sides are 3 and 4 seconds of arc on the Earth, how long is the "hypotenuse"? If 3 and 4 minutes of arc, then how long? Then 3 and 4 degrees? We can also throw in multiples of ten to keep the comparison simple. For example sides of 30 and 40 minutes of arc.
Frank Reed
