THIS is a sequel to the large “Plane Trigonometry” by the same writer, and is naturally drawn up on the same plan. Its size is handy, and yet it contains a very large amount of matter. Much of this ...

Most trigonometry students look at triangles on a flat surface. However, people from ancient astronomers to modern navigators calculated the arc lengths and angles of triangles on a sphere. They used ...

The Smithsonian collections are particularly rich in models for spherical trigonometry by Worcester, Massachusetts, high school teacher A. Harry Wheeler and his students. Examples of these models have ...