矩形相似性:通过旋转、镜像与缩放探索相似变换
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本范例演示了如何通过几何变换构造并验证两个矩形的相似性。核心数学概念是相似变换,包括旋转、镜像(反射)和缩放(位似),以及多边形相似的性质。作图要点包括:使用Segment、OrthogonalLine、Point、Intersect、Angle、Polygon等命令构造原始矩形及其角度;利用Line、Mirror、Rotate、Dilate命令对矩形进行镜像、旋转和缩放,生成新的矩形;通过Angle和Polygon命令度量并比较对应角与边长比例,从而验证相似关系。该范例适合初中高年级或高中学生,用于直观理解相似图形的判定条件,以及动态几何软件中变换工具的应用。
GeoGebra 命令及参数
Segment(A, B) → aOrthogonalLine(A, a) → bOrthogonalLine(B, a) → cPoint(b) → DOrthogonalLine(D, b) → dIntersect(c, d) → CSegment(D, A) → eSegment(D, C) → fSegment(C, B) → gAngle(C, B, A) → αAngle(B, A, D) → βAngle(A, D, C) → γAngle(D, C, B) → δPolygon(A, B, C, D) → poly1, a_1, b_1, c_1, d_1Line(E, F) → hMirror(A, h) → A'Mirror(B, h) → B'Mirror(C, h) → C'Mirror(D, h) → D'Polygon(A', B', C', D') → poly1', a', b', c', d'Point(Circle[G, Segment[B', C']]) → HRotate(H + (Segment[C', D'], 0), Angle[D' - C'] + Angle[H - G] - Angle[C' - B'], H) → IRotate(I + (Segment[D', A'], 0), Angle[A' - D'] + Angle[I - H] - Angle[D' - C'], I) → JPolygon(G, H, I, J) → poly3, g_1, h_1, i, jDilate(A, 0.5, K) → A'_1Dilate(B, 0.5, K) → B'_1Dilate(C, 0.5, K) → C'_1Dilate(D, 0.5, K) → D'_1Segment(A_1, B_1) → a_2OrthogonalLine(A_1, a_2) → b_2OrthogonalLine(B_1, a_2) → c_2Point(b_2) → D_1OrthogonalLine(D_1, b_2) → d_2Intersect(c_2, d_2) → C_1Segment(D_1, A_1) → e_1Segment(D_1, C_1) → f_1Segment(C_1, B_1) → g_2Angle(C_1, B_1, A_1) → α_1Angle(B_1, A_1, D_1) → β_1Angle(A_1, D_1, C_1) → γ_1Angle(D_1, C_1, B_1) → δ_1Dilate(A_1, 0.5, K_1) → A'_2Dilate(B_1, 0.5, K_1) → B'_2Dilate(C_1, 0.5, K_1) → C'_2Dilate(D_1, 0.5, K_1) → D'_2Dilate(A, 0.5, L) → A'_3Dilate(B, 0.5, L) → B'_3Dilate(C, 0.5, L) → C'_3Dilate(D, 0.5, L) → D'_3Segment(A_2, B_2) → a_4OrthogonalLine(A_2, a_4) → b_4OrthogonalLine(B_2, a_4) → c_4Point(b_4) → D_2OrthogonalLine(D_2, b_4) → d_4Intersect(c_4, d_4) → C_2Segment(D_2, A_2) → e_2Segment(D_2, C_2) → f_2Segment(C_2, B_2) → g_3Angle(C_2, B_2, A_2) → α_2Angle(B_2, A_2, D_2) → β_2Angle(A_2, D_2, C_2) → γ_2Angle(D_2, C_2, B_2) → δ_2Dilate(A_2, 0.5, L_1) → A'_4Dilate(B_2, 0.5, L_1) → B'_4Dilate(C_2, 0.5, L_1) → C'_4Dilate(D_2, 0.5, L_1) → D'_4Polygon(A'_4, B'_4, C'_4, D'_4) → poly1'_3, a'_1, b'_1, c'_1, d'_1Dilate(A, 1.5, M) → A'_5Dilate(B, 1.5, M) → B'_5Dilate(C, 1.5, M) → C'_5Dilate(D, 1.5, M) → D'_5Rotate(A'_5, 45°, N) → ORotate(B'_5, 45°, N) → PRotate(C'_5, 45°, N) → QRotate(D'_5, 45°, N) → RSegment(A_3, B_3) → a_3OrthogonalLine(A_3, a_3) → b_3OrthogonalLine(B_3, a_3) → c_3Point(b_3) → D_3OrthogonalLine(D_3, b_3) → d_3Intersect(c_3, d_3) → C_3Segment(D_3, A_3) → e_3Segment(D_3, C_3) → f_3Segment(C_3, B_3) → g_4Angle(C_3, B_3, A_3) → α_3Angle(B_3, A_3, D_3) → β_3Angle(A_3, D_3, C_3) → γ_3Angle(D_3, C_3, B_3) → δ_3Dilate(A_3, 1.5, M_1) → A'_6Dilate(B_3, 1.5, M_1) → B'_6Dilate(C_3, 1.5, M_1) → C'_6Dilate(D_3, 1.5, M_1) → D'_6Rotate(A'_6, 45°, N_1) → O_1Rotate(B'_6, 45°, N_1) → P_1Rotate(C'_6, 45°, N_1) → Q_1Rotate(D'_6, 45°, N_1) → R_1Polygon(O_1, P_1, Q_1, R_1) → poly2_1, o_1, p_1, q_1, r_1Dilate(A, 0.75, S) → A'_7Dilate(B, 0.75, S) → B'_7Dilate(C, 0.75, S) → C'_7Dilate(D, 0.75, S) → D'_7Rotate(A'_7, 90°, T) → URotate(B'_7, 90°, T) → VRotate(C'_7, 90°, T) → WRotate(D'_7, 90°, T) → ZSegment(A_4, B_4) → a_5OrthogonalLine(A_4, a_5) → b_5OrthogonalLine(B_4, a_5) → c_5Point(b_5) → D_4OrthogonalLine(D_4, b_5) → d_5Intersect(c_5, d_5) → C_4Segment(D_4, A_4) → e_4Segment(D_4, C_4) → f_4Segment(C_4, B_4) → g_5Angle(C_4, B_4, A_4) → α_4Angle(B_4, A_4, D_4) → β_4Angle(A_4, D_4, C_4) → γ_4Angle(D_4, C_4, B_4) → δ_4Polygon(A_4, B_4, C_4, D_4) → poly1_1, a_6, b_6, c_6, d_6Dilate(A_4, 0.75, S_1) → A'_8Dilate(B_4, 0.75, S_1) → B'_8Dilate(C_4, 0.75, S_1) → C'_8Dilate(D_4, 0.75, S_1) → D'_8Polygon(A'_8, B'_8, C'_8, D'_8) → poly1'_2, a'_2, b'_2, c'_2, d'_2Rotate(A'_8, 90°, T_1) → U_1Rotate(B'_8, 90°, T_1) → V_1Rotate(C'_8, 90°, T_1) → W_1Rotate(D'_8, 90°, T_1) → Z_1Polygon(U_1, V_1, W_1, Z_1) → poly2_2, u_1, v_1, w_1, z_2Polygon(E_2, F_2, 4) → poly2_3, p_2, q_2, r_2, s_1, G_2, H_2Segment(A_5, B_5) → a_9OrthogonalLine(A_5, a_9) → b_9OrthogonalLine(B_5, a_9) → c_7Point(b_9) → D_5OrthogonalLine(G_3, b_9) → p_3Intersect(b_9, p_3) → H_3Intersect(c_7, p_3) → I_2Polygon(A_5, H_3, I_2, B_5) → poly2_4, a_8, h_3, i_2, b_8Segment(A_6, B_6) → a_{11}OrthogonalLine(A_6, a_{11}) → b_{11}OrthogonalLine(B_6, a_{11}) → c_8Point(b_{11}) → D_6OrthogonalLine(G_4, b_{11}) → p_4Intersect(b_{11}, p_4) → H_4Intersect(c_8, p_4) → I_3Polygon(A_6, H_4, I_3, B_6) → poly2_5, a_{10}, h_4, i_3, b_{10}