The updated solucionario is particularly valuable here because spherical trig can be counterintuitive (e.g., spherical triangles can have two right angles, sums of angles exceed 180°). The solutions guide the reader through:
Trigonometría Plana y Esférica de William Anthony Granville
This is where Granville separates from the pack. Spherical trigonometry – the geometry of triangles on a sphere – is essential for:
Trigonometría Plana y Esférica de Granville: Todo sobre el Solucionario Actualizado