圆的几何构造与性质

GeoGebra 命令及参数

1. Circle(Centre, B) → Circle
2. Point(Circle) → C
3. CircleArc(Centre, B, C) → Arc
4. Point(Circle) → D
5. CircleSector(Centre, B, D) → Semicircle
6. Segment(Centre, C) → Radius
7. Mirror(C, Centre) → C'
8. Segment(C', C) → Diameter
9. CircleSector(Centre, B, C) → Sector
10. Rotate(C, 270°, Centre) → C'_1
11. CircleSector(Centre, C'_1, C) → Quadrant
12. Circle(Centre, B) → h
13. Angle(C'_1, Centre, C) → α
14. Point(Circle) → A
15. Segment(C, A) → Chord
16. Intersect(Circle, h, 1) → E
17. Tangent(C, Circle) → Tangent,