平行四边形、三角形、梯形的面积
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本范例演示了如何通过几何作图方法计算平行四边形、三角形和梯形的面积。涉及的核心数学概念包括相似变换、三角函数和向量。通过使用GeoGebra中的点、线段、旋转、镜像和平移等命令,可以直观地展示这些几何图形的性质。适合初中和高中学生学习几何和三角函数。
GeoGebra 命令及参数
Point(xAxis) → APoint(Circle[A, a]) → BSegment(A, B) → fPoint(f) → CPoint(Circle[C, b]) → DSegment(C, D) → gRotate(D, 90°, C) → D'Segment(A, D') → hLine(B, h) → iLine(D', f) → jIntersect(i, j) → EOrthogonalLine(B, xAxis) → kOrthogonalLine(D', k) → lIntersect(k, l) → FSegment(B, F) → mSegment(C, D') → nPolygon(A, D', F, B) → q1, a_1, d', f_1, b_1Polygon(F, E, B) → t1, b_2, f_2, eOrthogonalLine(A, d') → pLine(E, D') → qIntersect(p, q) → GPoint(Circle[F, μεταφορά]) → ΑSegment(F, Α) → rMirror(Α, F) → Α'Vector(F, Α') → uTranslate(F, u) → F'Translate(E, u) → E'Translate(B, u) → B'Polygon(F', E', B') → t1', b', f', e'Point(xAxis) → ΒPoint(Circle[Β, a]) → ΓSegment(Β, Γ) → sPoint(s) → ΔPoint(Circle[Δ, b]) → ΕSegment(Δ, Ε) → tRotate(Ε, 90°, Δ) → Ε'Polygon(Β, Ε', Γ) → t2, γ, β, ε'Segment(Ε', Δ) → cMidpoint(β) → ΖRotate(Β, α, Ζ) → Β'Rotate(Ε', α, Ζ) → Ε''Rotate(Γ, α, Ζ) → Γ'Polygon(Β', Ε'', Γ') → t2', γ', β', ε''Point(xAxis) → ΗPoint(Circle[Η, a]) → ΘSegment(Η, Θ) → dPoint(d) → ΙPoint(Circle[Ι, b]) → ΚSegment(Ι, Κ) → g_1Rotate(Κ, 90°, Ι) → Κ'Segment(Ι, Κ') → h_1OrthogonalLine(Κ', h_1) → i_1Point(i_1) → ΛSegment(Η, Κ') → j_1Segment(Κ', Λ) → k_1Segment(Λ, Θ) → l_1Segment(Θ, Η) → m_1Midpoint(l_1) → ΜPolygon(Η, Κ', Μ, Θ) → q2, η, κ', μ, θPolygon(Κ', Λ, Μ) → t3, μ_1, n_1, λRotate(Κ', α, Μ) → Κ''Rotate(Λ, α, Μ) → Λ'Rotate(Μ, α, Μ) → Μ'Polygon(Κ'', Λ', Μ') → t3', μ', κ'', λ'