探索风筝形(筝形)的性质
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① 本范例通过一个可交互的GeoGebra小程序,直观展示风筝形(筝形)的几何性质,用户可拖动顶点改变图形大小,并逐一验证其边、角、对称性等特征。② 核心数学概念包括筝形的定义(两组相邻边分别相等)、对角线垂直、对称轴、角相等性质,以及通过旋转、镜像等变换理解图形的对称性。③ 作图要点:构造中使用了Intersect(交点)、Point(点)、Line(直线)、Polygon(多边形)、Mirror(镜像)、Angle(角)、Segment(线段)等命令,创建了顶点A、B、C、D及镜像点A'、C',并生成多个多边形(poly1、poly1'、poly2)和辅助线段,通过角度α、β、γ、δ等标注性质。④ 适合初中至高中阶段学习平面几何的学生,用于课堂探究或自主发现筝形的性质,也可作为几何变换教学的辅助工具。
GeoGebra 命令及参数
Intersect(xAxis, yAxis) → APoint(xAxis) → CLine(A, C) → aPolygon(A, B, C) → poly1, c, a_1, bMirror(A, b) → A'Mirror(B, b) → DMirror(C, b) → C'Polygon(A', D, C') → poly1', c', a', b'Polygon(A, B, C, D) → poly2, a_2, b_1, c_1, b'_1Angle(A, B, C) → αAngle(C, D, A) → βAngle(D, A, B) → γAngle(B, C, D) → δSegment(A, C) → fLine(B, D) → gLine(A, C) → hIntersect(a, g) → D_1Segment(B, D_1) → iSegment(D_1, D) → jSegment(A, D_1) → kSegment(D_1, C) → lSegment(B, D_1) → mSegment(D_1, D) → pSegment(D_1, A) → qAngle(C, D_1, B) → εAngle(B, D_1, A) → ζAngle(A, D_1, D) → ηAngle(D, D_1, C) → θAngle(D_1, B, C) → ιAngle(C, D, D_1) → κAngle(D_1, D, A) → λAngle(D, A, D_1) → μAngle(D_1, A, B) → νAngle(A, B, D_1) → ξAngle(B, C, D_1) → οAngle(D_1, C, D) → ρSegment(B, D) → sPolygon(A, B, C, D) → poly3, a_3, b_2, c_2, d_1Segment(A, C) → e_1Segment(D, B) → f_1Segment(A, C) → rSegment(B, D) → g_1