Introduction

How can a triangle, a circle, and a wave all be three views of the same mathematical object? This is the introduction to a complete chapter on trigonometry. It lays out the whole journey in two great steps: first the right triangle, where six simple ratios let you measure inaccessible distances from a single angle and one known length; then the unit circle, which extends those ratios to every angle and reveals trigonometry's secret identity as the mathematics of repetition. From there the chapter pushes into identities, laws for solving any triangle, the deep links to π and e, and applications across surveying, astronomy, physics, music, and signal processing. In this introduction: Why the same ratios describe a triangle, a point on a circle, and a wave The two-step plan of the chapter: right triangle, then unit circle A preview of all ten sections to come What you need to start: only basic algebra and geometry This is Section 0 — the introduction — to Trigonometry, an 11-section chapter from The READY Academy. The full chapter playlist is linked in the description. #trigonometry #mathematics #stem #precalculus 00:00 Intro 01:52 The Journey Ahead