3 Isosceles Triangles with Common Vertex and Vertex Angle
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This example demonstrates the geometric construction and properties of three isosceles triangles sharing a common vertex and vertex angle. Key math concepts include isosceles triangles, vertex angles, rotation, midpoints, intersection points, and geometric transformations. The construction utilizes GeoGebra commands such as Rotate, Ray, Point, Polygon, Line, Midpoint, Intersect, Angle, Segment, and If. It is suitable for high school mathematics education, exploring symmetry and transformation relationships in isosceles triangles.
GeoGebra Commands & Parameters
Rotate(B, 120°, A) → B'Ray(A, B') → fPoint(f) → CRotate(B, α, A) → B'_1Polygon(B, A, B'_1) → poly1, b'_1, b, aLine(C, b) → hRotate(C, 120°, A) → C'_1Ray(A, C'_1) → gPoint(g) → DRotate(D, α, A) → D'Polygon(A, D, D') → poly3, d', a_2, dMidpoint(a_2) → GRotate(C, α, A) → C'Polygon(A, C, C') → poly2, c', a_1, c_1Line(B'_1, c') → iIntersect(h, i) → EAngle(B, A, B') → βAngle(B, A, B'_1) → γAngle(C, A, C') → δAngle(C, A, C'_1) → εMidpoint(a_1) → FMidpoint(a) → HLine(D, c_1) → jLine(C', d') → kIntersect(j, k) → ILine(D', b'_1) → lLine(B, d) → mIntersect(l, m) → JSegment(H, H + (t7 * (I - H))) → qSegment(G, G + (t7 * (E - G))) → pIntersect(p, q) → KSegment(F, F + (t7 * (J - F))) → n_1Segment(B, B + (t6 * (J - B))) → f_1Segment(D', D' + (t6 * (J - D'))) → eSegment(D, D + (t5 * (I - D))) → cSegment(C', C' + (t5 * (I - C'))) → tSegment(C, C + (t4 * (E - C))) → rSegment(B'_1, B'_1 + (t4 * (E - B'_1))) → sIf(t2 ≤ 1, Segment[A, A + (t2 * (C - A))], If[t2 ≤ 2, Segment[C, C + ((t2 - 1) * (C' - C))], Segment[C', C' + ((t2 - 2) * (A - C'))]]) → g_1If(t1 ≤ 1, Segment[A, A + (t1 * (B - A))], If[t1 ≤ 2, Segment[B, B + ((t1 - 1) * (B'_1 - B))], Segment[B'_1, B'_1 + ((t1 - 2) * (A - B'_1))]]) → h_1If(t3 ≤ 1, Segment[A, A + (t3 * (D - A))], If[t3 ≤ 2, Segment[D, D + ((t3 - 1) * (D' - D))], Segment[D', D' + ((t3 - 2) * (A - D'))]]) → i_1