任意三角形三外接正方形的三个结果现象
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本范例展示了在任意三角形的三边外分别作正方形,由此产生的三个有趣现象。核心数学概念包括三角形、正方形和几何变换。通过使用GeoGebra命令如Circle、Polygon、Dilate等进行构造。适合初中及以上学生或教师教学使用。
GeoGebra 命令及参数
Circle(A, b) → dPoint(d) → BCircle(B, c) → ePoint(e) → CPolygon(A, B, 4) → poly1, f, g, h, i, D, EPolygon(C, B, 4) → poly2, j, k, l, m, F, GMidpoint(D, A) → HMidpoint(F, C) → IDilate(B, If[0 < a ≤ 1, 1 - a, 0], A) → B'Dilate(B, If[0 < a ≤ 1, 1 - a, 0], F) → B'_1Segment(B, B') → nSegment(B, B'_1) → pRotate(B, If[1 < a ≤ 2, ((-(a - 1)) * π / 2), ((-π)) / 2], F) → B'_2Rotate(B'_1, If[1 < a ≤ 2, ((-(a - 1)) * π / 2), ((-π)) / 2], F) → LSegment(B'_2, L) → p'Rotate(B, If[1 < a ≤ 2, ((a - 1) * π / 2), π / 2], A) → B'_3Rotate(B', If[1 < a ≤ 2, ((a - 1) * π / 2), π / 2], A) → B''Segment(B'_3, B'') → n'Rotate(B'_2, If[2 < a ≤ 3, ((-(a - 2)) * π / 2), ((-π)) / 2], G) → MRotate(L, If[2 < a ≤ 3, ((-(a - 2)) * π / 2), ((-π)) / 2], G) → L'Segment(M, L') → p''Rotate(B'_3, If[2 < a ≤ 3, ((a - 2) * π / 2), π / 2], E) → NRotate(B'', If[2 < a ≤ 3, ((a - 2) * π / 2), π / 2], E) → B'''Segment(N, B''') → n''Rotate(N, If[3 < a ≤ 4, ((a - 3) * π / 2), π / 2], D) → N'Rotate(B''', If[3 < a ≤ 4, ((a - 3) * π / 2), π / 2], D) → OSegment(N', O) → n'''Rotate(M, If[3 < a ≤ 4, ((-(a - 3)) * π / 2), ((-π)) / 2], C) → M'Rotate(L', If[3 < a ≤ 4, ((-(a - 3)) * π / 2), ((-π)) / 2], C) → L''Segment(M', L'') → p'''Segment(F, G) → qSegment(F, B) → rSegment(A, B) → sMin(r, s) → oCircle(F, (0.15 * o)) → tIntersect(l, q) → PIntersect(t, q) → Q,Intersect(t, r) → R,CircleSector(F, Q, R) → c_1Dilate(F, If[4 < a ≤ 5, 5 - a, 0], C) → F'Vector(F, F') → uTranslate(c_1, u) → d_1Rotate(d_1, If[5 < a ≤ 6, ((a - 5) * π), π], C) → e_1Dilate(F, If[6 < a ≤ 7, 7 - a, 0], A) → F'_1Dilate(C, If[6 < a ≤ 7, 7 - a, 0], E) → C'Vector(F, F'_1) → vVector(C, C') → wTranslate(e_1, w) → f_1Translate(c_1, v) → g_1Line(A, p) → h_1Line(E, p''') → i_1Point(h_1) → SAngle(S, A, E) → αRotate(g_1, If[7 < a ≤ 8, ((-(a - 7)) * ((2 * π) - α)), (-((2 * π) - α))], A) → k_1Line(E, h_1) → j_1Point(j_1) → TAngle(D, E, T) → βRotate(f_1, If[7 < a ≤ 8, ((-(a - 7)) * β), (-β)], E) → p_1Dilate(E, If[8 < a ≤ 9, 9 - a, 0], G) → E'Dilate(F, If[8 < a ≤ 9, 9 - a, 0], D) → F'_2Vector(E, E') → u_1Vector(F, F'_2) → v_1Translate(p_1, u_1) → q_1Translate(c_1, v_1) → r_1Line(G, n'') → l_1Point(l_1) → ULine(G, n') → m_1Point(m_1) → VAngle(C, G, V) → γRotate(q_1, If[8 < a ≤ 9, ((-(a - 8)) * γ), (-γ)], E') → s_1Line(D, p) → n_1Point(n_1) → WAngle(W, D, B) → δRotate(r_1, If[8 < a ≤ 9, ((a - 8) * δ), δ], F'_2) → t_1Midpoint(A, B) → ZMidpoint(B, C) → A_1Midpoint(Z, B) → B_1Midpoint(A_1, B) → C_1Dilate(C, If[9 < a ≤ 10, 10 - a, 0], C_1) → C'_1Dilate(A, If[9 < a ≤ 10, 10 - a, 0], B_1) → A'Vector(A, A') → w_1Vector(C, C'_1) → a_1Translate(e_1, a_1) → c_2Translate(k_1, w_1) → d_2Rotate(d_2, If[10 < a ≤ 11, ((a - 10) * π / 2), π / 2], B_1) → e_2Rotate(c_2, If[10 < a ≤ 11, ((a - 10) * π / 2), π / 2], C_1) → f_2Dilate(C_1, If[11 < a ≤ 12, 12 - a, 0], B) → D_1Dilate(B_1, If[11 < a ≤ 12, 12 - a, 0], B) → E_1Vector(B_1, E_1) → b_1Vector(C_1, D_1) → u_2Translate(e_2, b_1) → g_2Translate(f_2, u_2) → h_2Dilate(F, If[12 < a ≤ 13, 13 - a, 0], I) → F'_3Segment(F, F'_3) → i_2Dilate(D, If[12 < a ≤ 13, 13 - a, 0], H) → D'Segment(D, D') → j_2Rotate(F, If[13 < a ≤ 14, ((a - 13) * π), π], I) → F'_4Rotate(F'_3, If[13 < a ≤ 14, ((a - 13) * π), π], I) → F_1Segment(F'_4, F_1) → k_2Rotate(D, If[13 < a ≤ 14, ((a - 13) * π), π], H) → D'_1Rotate(D', If[13 < a ≤ 14, ((a - 13) * π), π], H) → D''Segment(D'_1, D'') → l_2Dilate(B, If[21 < a ≤ 22, 22 - a, 0], I) → B'_4Dilate(B, If[21 < a ≤ 22, 22 - a, 0], H) → B'_5Vector(B, B'_4) → v_2Vector(B, B'_5) → w_2Line(I, p) → g_3Point(g_3) → N_1Line(H, n''') → l_3Point(l_3) → O_1Polygon(A, F, B) → poly3, b_2, a_2, f_3Circle(A, 2) → c_4Circle(F, 2) → d_4Polygon(F, A, 4) → poly4, i_4, j_4, k_4, l_4, C_2, D_2Dilate(A, If[0 < a ≤ 1, 1 - a, 0], C_2) → A'_1Segment(A, A'_1) → m_2Rotate(A, If[1 < a ≤ 2, ((-(a - 1)) * π / 2), ((-π)) / 2], C_2) → A'_2Rotate(A'_1, If[1 < a ≤ 2, ((-(a - 1)) * π / 2), ((-π)) / 2], C_2) → JSegment(A'_2, J) → n_2Rotate(A'_2, If[2 < a ≤ 3, ((-(a - 2)) * π / 2), ((-π)) / 2], D_2) → KRotate(J, If[2 < a ≤ 3, ((-(a - 2)) * π / 2), ((-π)) / 2], D_2) → J'Segment(K, J') → p_2Rotate(K, If[3 < a ≤ 4, ((-(a - 3)) * π / 2), ((-π)) / 2], F) → K'Rotate(J', If[3 < a ≤ 4, ((-(a - 3)) * π / 2), ((-π)) / 2], F) → J''Segment(K', J'') → q_2Angle(B, F, D_2) → εRotate(c_1, If[12 < a ≤ 13, ((a - 12) * ε), ε], F) → r_2Midpoint(A, D_2) → G_1Dilate(A, If[12 < a ≤ 13, 13 - a, 0], G_1) → A'_3Segment(A, A'_3) → s_2Rotate(A, If[13 < a ≤ 14, ((a - 13) * π), π], G_1) → A'_4Rotate(A'_3, If[13 < a ≤ 14, ((a - 13) * π), π], G_1) → H_1Segment(A'_4, H_1) → t_2Line(G_1, B) → h_3Line(A, I) → i_3Line(F, H) → j_3Intersect(i_3, j_3) → I_1Line(H, I) → k_3Distance(H, I) → distanceHIDistance(B, G_1) → distanceBG1Dilate(G_1, If[14 < a ≤ 15, 15 - a, 0], B) → J_1Segment(G_1, J_1) → m_3Dilate(A, If[15 < a ≤ 16, 16 - a, 0], I) → A'_5Segment(A, A'_5) → n_3Dilate(F, If[16 < a ≤ 17, 17 - a, 0], I_1) → F'_5Segment(F, F'_5) → p_3Dilate(I_1, If[17 < a ≤ 18, 18 - a, 0], H) → K_1Segment(I_1, K_1) → q_3Line(H, I) → r_3Line(B, G_1) → s_3Intersect(r_3, s_3) → L_1OrthogonalLine(C, r_3) → t_3Intersect(t_3, r_3) → M_1Line(H, I) → a_3Line(G_1, a_3) → b_3Rotate(G_1, If[18 < a ≤ 19, ((-(a - 18)) * π / 2), ((-π)) / 2], G_1) → P_1Rotate(J_1, If[18 < a ≤ 19, ((-(a - 18)) * π / 2), ((-π)) / 2], G_1) → Q_1Segment(P_1, Q_1) → c_3Dilate(G_1, If[19 < a ≤ 20, 20 - a, 0], H) → R_1Vector(G_1, R_1) → u_3Translate(P_1, u_3) → S_1Translate(Q_1, u_3) → T_1Segment(S_1, T_1) → d_3Dilate(C, If[20 < a ≤ 21, 21 - a, 0], M_1) → C'_2Vector(C, C'_2) → v_3Translate(e_1, v_3) → e_3Line(C, d_3) → f_4Point(f_4) → U_1Angle(G, C, U_1) → ζRotate(e_3, If[21 < a ≤ 22, ((a - 21) * ζ), ζ], M_1) → e_4Dilate(M_1, If[22 < a ≤ 23, 23 - a, 0], L_1) → V_1Vector(M_1, V_1) → w_3Translate(e_4, w_3) → g_4Line(I_1, B) → h_4Circle(B, 1) → p_4Intersect(p_4, h_4, 2) → W_1Ray(I_1, B) → m_4Circle(G_1, 2) → q_4Intersect(q_4, s_3, 2) → Z_1Ray(G_1, Z_1) → n_4