圆的割线和角度
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所属专题
Circles
①本范例演示了如何在圆上通过移动点创建割线和角度;②涉及核心数学概念包括割线定理、圆周角定理、角度测量;③作图要点:使用 GeoGebra 命令 Circle(圆)、Line(线)、OrthogonalLine(垂线)、Intersect(交点)、Rotate(旋转)、CircleArc(圆弧)、Point(点)、Segment(线段)、Angle(角度)、CircleSector(扇形)、Dilate(缩放);④适合高中数学教学和几何作图练习。
GeoGebra 命令及参数
Circle(A, 5) → cLine(A, a) → bOrthogonalLine(A, a) → dIntersect(c, d, 2) → BRotate(B, 45*°, A) → B'Rotate(B, -45*°, A) → B'_1OrthogonalLine(B', a) → eOrthogonalLine(B'_1, a) → fIntersect(c, e, 1) → CIntersect(c, f, 1) → DCircleArc(A, B'_1, B') → gCircleArc(A, C, D) → hPoint(g) → EPoint(h) → FCircleArc(A, D, B'_1) → kPoint(k) → GPoint(k) → HLine(E, H) → iLine(G, F) → jIntersect(i, j) → ISegment(I, E) → lSegment(I, G) → mSegment(I, H) → nSegment(I, F) → pAngle(H, A, G) → αAngle(E, A, F) → βRotate(E, (-α), A) → E'Angle(H, A, G) → γAngle(E, I, F) → δCircleArc(A, E, F) → qCircleArc(A, E', E) → rCircleArc(A, E, E') → sCircleSector(A, E, F) → tDilate(A, 0.05, E) → A'Rotate(A', (-α), A) → A''CircleArc(A, E, E') → c_1CircleArc(A, E, A'') → d_1CircleArc(A, A', A'') → e_1Dilate(A, 0.05, F) → A'_1Rotate(A'_1, (-δ), A) → LRotate(L, (-δ), A) → L'CircleArc(A, H, G) → f_1CircleArc(A, G, H) → g_1Circle(I, Segment[A, A'_1]) → h_1Intersect(h_1, p, 1) → MIntersect(h_1, l, 1) → NCircleArc(I, N, M) → k_1CircleArc(A, L, F) → p_1CircleArc(A, L', L) → q_1Segment(L, A) → a_1Segment(F, A) → b_1Segment(L', A) → i_1Segment(E, A) → j_1Angle(L', A, L) → εAngle(L, A, F) → ζSegment(A, F) → l_1