# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

**Re: Mathematical Question**

**From:**Robert J. Park

**Date:**2002 Sep 19, 18:29 -0700

If you are comparing an Arc on a Circle to
something on a Sphere, you can also have an Arc on a Sphere, but you are
probably thinking in terms of a Spherical Triangle. As Brian
listed, there are several names that could apply, but Spherical Triangle is the
most common. When it is placed in 2 dimensions, some of my students
refer to it as a "Bulging Triangle" because of the curved sides. That is
because all three side are actually Arcs on the surface of the
Sphere.

Bob Park

rjpark2---bi.com

rjpark2---bi.com

PhD - Mathematics

Some or us - the Dreamers - were born to dance upon
the wind.

----- Original Message -----From:Robert EnoSent:Thursday, September 19, 2002 5:30 PMSubject:Mathematical QuestionGreetings list,Given the rather esoteric nature of some of the recent discussions, I am hopeful that one of you will have the answer to a long-standing question of mine.What is the term used to describe a small 2 dimensional section of a sphere? Or to put it another way, if a small section of a circle is called an "arc", what is the equivalent in a sphere?