动画258:等边三角形内切圆
几何画板及绘图内容加载中,请稍等……
这个范例演示了等边三角形的内切圆。涉及的核心数学概念包括三角形、内切圆和等边三角形。通过使用GeoGebra命令如Polygon、Centroid、Tangent和Dilate等,可以构造出等边三角形及其内切圆。适合初中和高中学生学习几何作图和内切圆的相关知识。
GeoGebra 命令及参数
Polygon(A, B, 3) → poly1, f, g, h, CSegment(A, B) → iSegment(B, C) → jSegment(C, A) → kCentroid(poly1) → DOrthogonalLine(D, g) → lOrthogonalLine(D, i) → mIntersect(l, g) → ECircle(D, E) → cAngle(B, A, C) → αRotate(B, 30°, A) → B'Angle(B, A, B') → βLine(A, B') → nIntersect(c, n, 1) → FMidpoint(A, F) → GTangent(F, c) → p,Intersect(p, i) → HIntersect(p, h) → IPolygon(A, H, I) → poly2, i_1, a, h_1Centroid(poly2) → JCircle(J, F) → dIntersect(c, m, 2) → KTangent(K, c) → q,Intersect(q, g) → LIntersect(q, h) → MPolygon(M, L, C) → poly3, c_1, m_1, l_1Centroid(poly3) → NLine(B, D) → rIntersect(h, k) → OIntersect(r, h) → PIntersect(c, r) → Q, RTangent(Q, c) → s,Intersect(s, g) → SIntersect(s, i) → TPolygon(T, B, S) → poly4, s_1, t, bCentroid(poly4) → UCircle(U, Q) → d_1Dilate(A, If[0 < o ≤ 1, 1 - o, 0], B) → A'Segment(A, A') → a_1Rotate(A, If[1 < o ≤ 2, ((o - 1) * π / 3), π / 3], A) → A'_1Rotate(A', If[1 < o ≤ 2, ((o - 1) * π / 3), π / 3], A) → A''Segment(A'_1, A'') → b_1Rotate(A, If[2 < o ≤ 3, ((-(o - 2)) * π / 3), ((-π)) / 3], B) → A'_2Rotate(A', If[2 < o ≤ 3, ((-(o - 2)) * π / 3), ((-π)) / 3], B) → A''_1Segment(A'_2, A''_1) → e_1Intersect(d, dd, 1) → W_1Intersect(dd, a_1) → Z_1, A_1Intersect(ddd, a_1) → A_2, B_1Center(cc) → B_2OrthogonalLine(B_2, e_1) → k_3Intersect(k_3, e_1) → C_2Angle(B_2, C_2, B) → ιTangent(C_2, dd) → l_3, m_3Intersect(dd, l_3) → VCenter(dd) → C_1Center(ddd) → D_1Dilate(B_2, If[3.5 < o ≤ 4.5, 4.5 - o, 0], C_2) → E_1Dilate(C_1, If[3.5 < o ≤ 4.5, 4.5 - o, 0], A_1) → F_1Dilate(D_1, If[3.5 < o ≤ 4.5, 4.5 - o, 0], A_2) → G_1Segment(B_2, E_1) → f_1Segment(D_1, G_1) → g_1Segment(C_1, F_1) → j_1Angle(C_1, V, C_2) → δOrthogonalLine(C_1, a_1) → k_1Intersect(k_1, a_1) → H_1Angle(C_1, H_1, A) → γOrthogonalLine(D_1, a_1) → n_1Intersect(n_1, a_1) → I_1Angle(B, I_1, D_1) → εDilate(C_1, If[4.5 < o ≤ 5.5, 5.5 - o, 0], V) → K_1Segment(C_1, K_1) → p_1Dilate(C_2, If[5.5 < o ≤ 6.5, 6.5 - o, 0], V) → L_1Segment(C_2, L_1) → q_1Dilate(H_1, If[5.5 < o ≤ 6.5, 6.5 - o, 0], I_1) → M_1Dilate(V, If[6.5 < o ≤ 7.5, 7.5 - o, 0], C_1) → V'Vector(V, V') → uTranslate(C_2, u) → WTranslate(L_1, u) → ZSegment(W, Z) → eLine(A, B) → r_1Line(V, r_1) → t_1Point(t_1) → N_1Angle(N_1, V, C_2) → ζRotate(W, If[7.5 < o ≤ 8.5, ((-(o - 7.5)) * ζ), (-ζ)], C_1) → W'Rotate(Z, If[7.5 < o ≤ 8.5, ((-(o - 7.5)) * ζ), (-ζ)], C_1) → Z'Segment(W', Z') → e'