莫利等边三角形
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①本范例演示了莫利三角形定理,即任意三角形的三个内角三等分线的交点构成的三角形是等边三角形;②涉及核心数学概念包括等边三角形、角平分线、旋转、相交线、单位圆等;③作图要点:使用Polygon命令构建三角形,Angle命令获取角度,Rotate命令进行旋转,Ray命令生成射线,Intersect命令求交点,Line命令绘制直线;④适合高中数学教学和几何爱好者探索。
GeoGebra 命令及参数
Polygon(A, B, C) → poly1, c, a, bAngle(B, A, C) → αAngle(A, C, B) → βAngle(C, B, A) → γRotate(B, α / 3, A) → B'Angle(B, A, B') → δRay(A, B') → fRotate(B', α / 3, A) → B''Angle(B', A, B'') → εRay(A, B'') → gRotate(C, γ / 3, B) → C'Angle(C, B, C') → ζRay(B, C') → hRotate(C', γ / 3, B) → C''Angle(C', B, C'') → ηRay(B, C'') → iRotate(A, β / 3, C) → A'Angle(A, C, A') → θRay(C, A') → jRotate(A', β / 3, C) → A''Angle(A', C, A'') → ιRay(C, A'') → kIntersect(h, k) → DIntersect(f, i) → EIntersect(g, j) → FPolygon(D, E, F) → poly2, f_1, d, eRotate(A, (180° - γ) / 3, B) → A'_1Angle(A, B, A'_1) → μLine(B, A'_1) → nRotate(A'_1, (180° - γ) / 3, B) → HAngle(A'_1, B, H) → νLine(B, H) → pRotate(B, (180° - β) / 3, C) → B'_3Angle(B, C, B'_3) → ξLine(C, B'_3) → qRotate(B'_3, (180° - β) / 3, C) → IAngle(B'_3, C, I) → οLine(C, I) → rRotate(C, (180° - α) / 3, A) → C'_1Angle(C, A, C'_1) → κLine(A, C'_1) → lRotate(C'_1, (180° - α) / 3, A) → GAngle(C'_1, A, G) → λLine(A, G) → mIntersect(n, f) → JIntersect(r, g) → KIntersect(l, j) → LIntersect(p, k) → MIntersect(m, i) → NIntersect(q, h) → OIntersect(n, m) → PIntersect(p, q) → QIntersect(r, l) → RPolygon(Q, K, J) → poly3, j_1, q_1, k_1Polygon(L, P, M) → poly4, m_1, l_1, p_1Polygon(N, R, O) → poly5, o, n_1, r_1Polygon(P, Q, R) → poly6, r_2, p_2, q_2