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2. Beta
1

Angle Bisector
教程关无解析

Tutorial: Angle Bisector
2

Intersection of Angle Bisectors
3

Angle of 30°
4

Double Angle
5

Cut Rectangle
6

Drop a Perpendicular
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Erect a Perpendicular
教程关无解析

Tutorial: Perpendicular
8

Tangent to Circle at Point
9

Circle Tangent to Line
10

Сircle in Rhombus