圆内接四边形对角互补(含切线-弦角)
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①本范例演示圆内接四边形的对角互补性质,并展示切线与弦形成的角;②核心概念包括圆内接四边形、对角互补、切线角、弦切角;③作图要点:使用 Circle, Point, Intersect, Tangent, CircleArc, Segment, Angle, CircleSector, Rotate 等命令构造图形;④适合高中数学教学,用于理解圆与四边形的关系及角度性质。
GeoGebra 命令及参数
Circle(O, 1) → cPoint(c) → CCircle(C, 0.3) → qIntersect(c, q, 2) → PPoint(c) → AIntersect(c, q, 1) → NTangent(A, c) → j,CircleArc(O, N, A) → dPoint(d) → DCircleArc(O, A, P) → ePoint(e) → BSegment(C, D) → fSegment(D, A) → gSegment(A, B) → hSegment(B, C) → iCircle(A, 1.5) → pIntersect(p, j, 2) → FIntersect(p, j, 1) → EIf(k ≤ 1, k, 1) → k1If(k ≤ 1, 0, 1 < k ≤ 2, k - 1, 1) → k2If(k ≤ 2, 0, 2 < k ≤ 3, k - 2, 1) → k3If(k ≤ 3, 0, 3 < k ≤ 4, k - 3, 1) → k4Segment(G, H) → lSegment(C, I) → mAngle(B, A, D) → αIntersect(q, f, 1) → JIntersect(q, i, 1) → KIntersect(q, m, 1) → LCircleSector(C, J, L) → s1CircleSector(C, L, K) → s2Rotate(Translate[s1, Vector[(k3 * Vector[C, A])]], ((-k3) * Angle[A, D, C]), M) → s1'Rotate(Translate[s2, Vector[(k3 * Vector[C, A])]], (k3 * Angle[C, B, A]), M) → s2'Angle(D, C, B) → r