Cell phone towers. Baseball fields. Your gym workout. Office buildings. GPS directions. Infinite examples show why trigonometry is important to your everyday life. Often shortened to "trig", trigonometry is the discipline of mathematics that studies triangles. Introductory trigonometry textbooks will establish foundational ideas of angles, radians, sine, cosine, and tangent, while more advanced functions of this mathematics field are required studies for engineering, physics, and astronomy.