直角三角形内切圆与外切圆动态演示
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①本范例动态演示直角三角形的内切圆与外切圆的几何关系;②涉及核心概念:直角三角形、内切圆、外切圆、切线、旋转、相似三角形;③作图要点:使用 GeoGebra 命令如 Intersect(交点)、Semicircle(半圆)、Polygon(多边形)、Rotate(旋转)、Dilate(缩放)等构建图形;④适合高中数学教学,用于理解特殊四边形与圆的几何性质。
GeoGebra 命令及参数
Intersect(xAxis, yAxis) → ASemicircle(A, B) → cPoint(c) → CPolygon(A, C, B) → t1, b, a_1, c_1Angle(B, A, C) → αRotate(B, α / 2, A) → B'Angle(B, A, B') → βRay(A, B') → fRotate(A, π / 4, C) → A'Ray(C, A') → gRay(A, C) → hRay(A, B) → iSegment(B, C) → jIntersect(g, f) → DRay(B, B + (1, 0, 0)) → kPoint(k) → ECircle(C, 3) → dIntersect(d, h, 2) → FAngle(E, B, C, xOyPlane) → γRotate(E, γ / 2, B) → E'Ray(B, E') → lRotate(B, π / 4, C) → B'_1Ray(C, B'_1) → mIntersect(l, m) → GOrthogonalLine(D, h) → nOrthogonalLine(D, k, xOyPlane) → pIntersect(n, h) → HIntersect(p, i) → IOrthogonalLine(G, h, xOyPlane) → qOrthogonalLine(G, k, xOyPlane) → rIntersect(q, h) → JIntersect(r, i) → KCircle(G, J, xOyPlane) → eCircle(D, H) → sRay(B, D) → tAngle(A, C, B) → δRay(B, D) → f_1Ray(A, D) → g_1Min({Distance[A, D], Distance[B, D], Distance[B, G], Distance[C, G]}) → oCircle(A, (0.35 * o)) → d_1Intersect(d_1, i) → L,Circle(B, (0.35 * o)) → e_1Circle(C, (0.35 * o)) → h_1Intersect(h_1, h, 2) → MIntersect(k, e_1) → N,Intersect(e_1, j) → O,Dilate(A, If[0 < u ≤ 1, 1 - u, 0], D) → A'_1Segment(A, A'_1) → i_1Dilate(B, If[0 < u ≤ 1, 1 - u, 0], D) → B'_2Segment(B, B'_2) → j_1Rotate(O, If[0 < u ≤ 1, (u * (π / 2 - α) / 2), (π / 2 - α) / 2], B) → O'Rotate(L, If[0 < u ≤ 1, (u * β), β], A) → L'CircleSector(B, O, O') → k_1CircleSector(A, L, L') → p_1Dilate(C, If[1 < u ≤ 2, 2 - u, 0], G) → C'Dilate(B, If[1 < u ≤ 2, 2 - u, 0], G) → B'_3Segment(B, B'_3) → l_1Segment(C, C') → m_1Intersect(h_1, j) → P,Rotate(P, If[1 < u ≤ 2, ((u - 1) * π / 4), π / 4], C) → P'Rotate(N, If[1 < u ≤ 2, ((u - 1) * γ / 2), γ / 2], B) → N'CircleSector(B, N, N', xOyPlane) → q_1CircleSector(C, P, P') → r_1Rotate(p_1, If[2.5 < u ≤ 3.5, ((u - 2.5) * β), β], A) → s_1Rotate(k_1, If[2.5 < u ≤ 3.5, ((u - 2.5) * (π / 2 - α) / 2), (π / 2 - α) / 2], B) → t_1Rotate(q_1, If[3.5 < u ≤ 4.5, ((u - 3.5) * γ / 2), γ / 2], B) → c_2Rotate(r_1, If[3.5 < u ≤ 4.5, ((u - 3.5) * π / 4), π / 4], C) → d_2Dilate(D, If[5 < u ≤ 6, 6 - u, 0], H) → D'Circle(D, D') → e_2OrthogonalLine(D, j) → n_1Intersect(j, n_1) → QDilate(G, If[6 < u ≤ 7, 7 - u, 0], J) → G'Circle(G, G', xOyPlane) → f_2OrthogonalLine(G, j, xOyPlane) → b_1Intersect(b_1, j) → RDilate(H, If[12 < u ≤ 13, 13 - u, 0], R) → H'Dilate(R, If[13 < u ≤ 14, 14 - u, 0], K) → R'Ray(C, J) → i_2Segment(A, C) → j_2Dilate(D, If[16 < u ≤ 17, 17 - u, 0], R) → D'_1Ray(K, R) → m_2Ray(J, Q) → n_2Intersect(m_2, n_2) → UDilate(K, If[12 < u ≤ 13, 13 - u, 0], R) → K'Dilate(J, If[12 < u ≤ 13, 13 - u, 0], Q) → J'Segment(J, J') → p_2Segment(K, K') → q_2Dilate(R, If[13 < u ≤ 14, 14 - u, 0], U) → R'_1Dilate(Q, If[13 < u ≤ 14, 14 - u, 0], U) → Q'Segment(Q, Q') → g_2Segment(R, R'_1) → k_2Dilate(J, If[14 < u ≤ 15, 15 - u, 0], K) → J'_1Segment(J, J'_1) → l_2Polygon(J, U, K) → t2, k_3, j_3, u_1Dilate(C, If[16 < u ≤ 17, 17 - u, 0], J) → C'_1Vector(C, C'_1) → vTranslate(d_2, v) → h_2Line(C, p_2) → r_2Point(r_2) → SAngle(S, C, G, xOyPlane) → εRotate(h_2, If[16 < u ≤ 17, ((-(u - 16)) * ε), (-ε)], C'_1) → s_2Dilate(J, If[18 < u ≤ 19, 19 - u, 0], K) → J'_2Vector(J, J'_2) → wTranslate(s_2, w) → t_2Line(K, p_2) → a_2Point(a_2) → TRotate(t_2, If[18 < u ≤ 19, (((-(u - 18)) * 3) * π / 4), (-3 * π / 4)], J'_2) → c_3