4.2 Measures, Shape & Space 度量、圖形與空間

Basic properties of circles 圓的基本性質

• gMath: 圓的基本性質 | Basic Properties of Circles

• Converses of Theorems on Circle Properties

• Circles, angles and chords

Locus 軌跡

• gMath: 軌跡 | Loci

• 軌跡（教師版）

• Upside Down?

Equations of straight lines and circles 直線與圓的方程

• gMath: 直線方程 | Equation of Straight Lines

• gMath: 圓的方程 | Equation of Circles

More about trigonometry 續三角

• gMath: 續三角學 | More about Trigonometry

• Defining Trigonometric Ratios

• Trigonometric Graphs and the Unit Circle

• Six Trigonometric Graphs and the Unit Circle

• gMath: 續三角學的應用 | More about Applications of Trigonometry