十三分之四三角形
几何画板及绘图内容加载中,请稍等……
①本范例演示了内三角形与外三角形面积比为四比十三的几何构造;②涉及的核心数学概念包括等边三角形、向量、旋转与面积比计算;③作图要点——使用Polygon(多边形)、Midpoint(中点)、Segment(线段)、Ray(射线)、Intersect(交点)、Rotate(旋转)、Point(点)等GeoGebra命令构建图形;④适合高中数学教学,用于理解几何变换与面积比例关系。
GeoGebra 命令及参数
Polygon(A, B, C) → t1, c, a, bMidpoint(c) → XMidpoint(a) → YMidpoint(b) → ZSegment(X, B) → fSegment(B, Y) → gSegment(Y, C) → hSegment(C, Z) → iSegment(Z, A) → jSegment(A, X) → kMidpoint(k) → G_1Midpoint(g) → IMidpoint(i) → KRay(A, I) → lRay(C, G_1) → mRay(B, K) → nIntersect(l, m) → DIntersect(l, n) → EIntersect(m, n) → FPolygon(D, E, F) → t2, l_1, h_1, j_1Segment(B, F) → pSegment(A, E) → qSegment(C, D) → rMidpoint(j_1) → QMidpoint(l_1) → GMidpoint(h_1) → MPolygon(B, Y, M) → t3, m_1, b_1, y_1Polygon(C, Q, Z) → t4, z_1, c_1, h_2Polygon(A, G, X) → t5, x_1, a_1, l_2Rotate(B, (-α), Y) → B'Rotate(Y, (-α), Y) → Y'Rotate(M, (-α), Y) → H'Polygon(B', Y', H') → t3', m', b', y'Rotate(C, (-α), Z) → C'Rotate(Q, (-α), Z) → I'Rotate(Z, (-α), Z) → Z'Polygon(C', I', Z') → t4', z', c', h'Rotate(A, (-α), X) → A'Rotate(G, (-α), X) → G'Rotate(X, (-α), X) → X'Polygon(A', G', X') → t5', x', a', l'Midpoint(y') → HMidpoint(z') → JMidpoint(x') → LPoint(l_1) → NSegment(N, H) → sPoint(j_1) → PSegment(E, L) → eSegment(H, F) → f_1Segment(J, D) → g_1Intersect(z', h') → RIntersect(z', g_1) → OPoint(l') → SPolygon(G', S, E, N) → q1, g', s_1, e_1, n_1Intersect(m', y') → TPoint(h_1) → UPolygon(T, F, U, H') → q3, t_1, f_2, u, i_1Segment(U, O) → tPolygon(A, I', Q, D) → q2, a_2, i', q_1, dSegment(Q, L) → k_1