trigonometric
adjective /ˌtrɪɡənəˈmetrɪk/
  /ˌtrɪɡənəˈmetrɪk/
(also trigonometrical 
 (mathematics /ˌtrɪɡənəˈmetrɪkl/
  /ˌtrɪɡənəˈmetrɪkl/
)- connected with the type of mathematics that deals with the relationship between the sides and angles of triangles三角学