Trigonometry explores the relationship between sides and angles in right-angled triangles ... side divided by the adjacent side is called the tangent of the angle and is abbreviated to tan.

NCERT Class 10 Maths Chapter 8 Introduction to Trigonometry ... cos C Sol. In triangle ΔABC with right angle at B, ∠B = 90° ...

Luckily, triangles survived nonetheless—and thrived. In “Love Triangle: How Trigonometry Shapes the World,” Matt Parker ...