UNIT OVERVIEW

Trigonometry comes from Greek words meaning "triangle measurement." This branch of mathematics uses the ratios between sides of right-angled triangles to solve problems involving angles and distances.

You already know about triangles from earlier grades. In this unit, you will learn how the ratios between the sides of right-angled triangles create powerful tools for solving real-world problems. These ratios—sine, cosine, and tangent—are the foundation of trigonometry.

What You Will Learn

• How to define and calculate sine, cosine, and tangent ratios in right-angled triangles
• The reciprocal ratios: cosecant, secant, and cotangent
• How to find exact values for special angles ($0°$, $30°$, $45°$, $60°$, $90°$) without a calculator
• How to extend trigonometric definitions to angles from $0°$ to $360°$ using the Cartesian plane
• How to solve two-dimensional problems involving right-angled triangles
• How to solve simple trigonometric equations for angles between $0°$ and $90°$

Real-Life Applications

1. Construction: Builders use trigonometry to calculate roof angles and rafter lengths.
2. Navigation: Pilots calculate flight paths and distances using trigonometric principles.
3. Surveying: Land surveyors measure distances and angles without physically measuring every length.
4. Sports: Angle and distance calculations in activities like rugby goal-kicking use trigonometry.

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