相似三角形SSS相似性作图示例
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该范例演示了如何通过边长比例判断三角形相似性。核心数学概念包括相似三角形的定义、SSS相似准则以及几何作图技巧。作图要点涉及使用GeoGebra命令如Rotate、Polygon、Intersect等来构造三角形,并分析边长关系。适合初中或高中数学教学,用于理解相似三角形的基本原理和作图方法。
GeoGebra 命令及参数
Rotate((Random[30, 50] / 10, 0), Random[20, 100]°, A) → BPolygon(A, B, C) → t1, cLen, aLen, bLenIf(ABmaxLenCase3 > BCmaxLenCase3, sqrt(ABmaxLenCase3^(2) - BCmaxLenCase3^(2)), x(TRviewBox) - x(A)) → ACmaxLenCase3Polygon(BLviewBox, (x(BLviewBox), y(TRviewBox)), TRviewBox, (x(TRviewBox), y(BLviewBox))) → viewBox, vbLeft, vbTop, vbRight, vbBottomIntersect(Ray[A, A + (ACmaxLenCase3, BCmaxLenCase3)], viewBox) → MaxB3InRegionPolygon(A, MaxB3InRegion, (x(TRviewBox), y(MaxB3InRegion)), (x(TRviewBox), y(A))) → restrictedB3Range, f, g, h, jIf(ABmaxLenCase3 > ACmaxLenCase3, Intersect[Circle[A, ABmaxLenCase3], Ray[(ACmaxLenCase3, 0), (ACmaxLenCase3, 5)]], TRviewBox) → MaxB3If(aLen < cLen, restrictedB3Range, Polygon[(x(BLviewBox), y(A)), (x(BLviewBox), y(TRviewBox)), TRviewBox, (x(TRviewBox), y(A))]) → B3rangePointIn(B3range) → B3Circle(A, Segment[A, B3]) → cAlenAB3UnitVector(Vector[A, B]) → uABPoint(Segment[A, Intersect[Ray[A, B], viewBox]]) → B4Line(B4, Vector[B, C]) → b4LineIntersect(Ray[A, C], b4Line) → C4'UnitVector(Vector[A, C]) → uACPoint(Segment[A, Intersect[Ray[A, C], viewBox]]) → C4Polygon(A, B4, C4') → t4b, t4b_c, t4b_a, t4b_bLine(C4, Vector[C, B]) → c4LineIntersect(Ray[A, B], c4Line) → B4'Polygon(A, B4', C4) → t4c, t4c_c, t4c_a, t4c_bRay((ACmaxLenCase3, 0), (ACmaxLenCase3, 2)) → iCircle(B4, BClenCase3b) → cBlenBC4Circle(B3, BClenCase3b) → cBlenBC3Segment((C3start, y(A)), (C3end, y(A))) → C3rangePoint(C3range) → C3Circle(C3, BClenCase3b) → cC3lenBCLength(Segment[A, B3]) → ABlenCase3Intersect(cAlenAB3, cC3lenBC) → B3', B3'_1, ,Polygon(A, B3', C3) → t3c, t3c_c, t3c_a, t3c_bPointIn(viewBox) → B1Point(Segment[A, (x(TRviewBox), y(A))]) → C2Point(Segment[A, (x(TRviewBox), y(A))]) → C1Polygon(A, B1, C1) → tCase1, tCase1_c, tCase1_a, tCase1_bPointIn(viewBox) → B2Intersect(Circle[A, AClenCase2a], Ray[A, C]) → C2',Polygon(A, B2, C2') → tCase2b, tCase2b_c, tCase2b_a, tCase2b_bIntersect(Circle[A, ABlenCase2b], Ray[A, B2]) → B2',Polygon(A, B2', C2) → tCase2c, tCase2c_c, tCase2c_a, tCase2c_bIf(bActive, If[caseNum ≟ 4, B4, If[caseNum ≟ 3, B3, If[caseNum ≟ 2, B2, B1]]], If[caseNum ≟ 4, B4', If[caseNum ≟ 3, B3', If[caseNum ≟ 2, B2', B1]]]) → B'lblPointIntersect(cBlenBC3, Ray[A, C]) → C3'_1, C3'_2If(Defined[C3'_2], C3'_2, C3'_1) → C3'Polygon(A, B3, C3') → tCase3b, tCase3b_c, tCase3b_a, tCase3b_bIf(bActive, If[caseNum ≟ 4, C4', If[caseNum ≟ 3, C3', If[caseNum ≟ 2, C2', C1]]], If[caseNum ≟ 4, C4, If[caseNum ≟ 3, C3, If[caseNum ≟ 2, C2, C1]]]) → C'lblPt
AI 绘图提示语参考
绘制三个全等三角形,首先在平面上随机选取三个点A、B、C,构造三角形ABC。然后以A为圆心,AB、AC为半径画圆,找到圆与边BC的交点B3和C3,再通过旋转和交点构造方法找到B4和C4,最终形成三个相似三角形,分别是△AB3C3、△AB4C4和△ABC。
以上提示语为根据原始绘图命令整理而来,仅供参考。