A significant portion of the Geometry & Trigonometry syllabus topic (especially SL) focuse on trigonometry - and a big part of the trigonometry content involves what I would refer to as "triangle" trigonometry. This is trigonometry that involves triangles (obviously), both right and non-right triangles, and includes items such as: using trig functions to find sides & angles of a triangle, sine rule, cosine rule, angles...