菱形面积计算
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本范例演示如何通过构造菱形的对角线来计算其面积。涉及的核心数学概念包括菱形的性质、对角线互相垂直平分以及面积公式。作图要点包括使用 GeoGebra 命令如 Segment(线段)、LineBisector(角平分线)、Point(点)、Intersect(交点)、Polygon(多边形)、Midpoint(中点)、Rotate(旋转)和 Angle(角度)等来构建菱形并计算面积。适合初中及以上学生学习几何作图和面积计算。
GeoGebra 命令及参数
Segment(A, B) → ABLineBisector(AB) → bPoint(b) → CPoint(b) → DSegment(C, A) → cSegment(D, A) → dSegment(B, D) → eSegment(C, B) → fIntersect(b, AB) → EPolygon(C, E, A) → poly1, a_1, c_1, e_1Polygon(C, E, B) → poly2, b_1, c_2, e_2Polygon(A, E, D) → poly3, d_4, a_2, e_3Polygon(E, B, D) → poly4, d_3, e_4, b_2Midpoint(C, A) → FMidpoint(C, B) → GMidpoint(A, D) → HMidpoint(D, B) → IRotate(A, rotateΔ, H) → A'Rotate(E, rotateΔ, H) → E'Rotate(D, rotateΔ, H) → D'Polygon(A', E', D') → poly3', d', a', e'Rotate(C, rotateΔ, F) → C'Rotate(E, rotateΔ, F) → E'_1Rotate(A, rotateΔ, F) → A'_1Polygon(C', E'_1, A'_1) → poly1', a'_1, c', e'_1Rotate(C, rotateΔ, G) → C'_1Rotate(E, rotateΔ, G) → E'_2Rotate(B, rotateΔ, G) → B'Polygon(C'_1, E'_2, B') → poly2', b', c'_1, e'_2Rotate(E, rotateΔ, I) → E'_3Rotate(B, rotateΔ, I) → B'_1Rotate(D, rotateΔ, I) → D'_1Polygon(E'_3, B'_1, D'_1) → poly4', d'_1, e'_3, b'_1Segment(D, C) → CDMidpoint(A, E) → JMidpoint(D, C) → KAngle(C, E, A) → αMidpoint(E, B) → LSegment(A, E) → aSegment(E, B) → gSegment(C, E) → iSegment(D, E) → jPolygon(D, C, A) → poly5, a_3, d_5, c_3Polygon(D, C, B) → poly6, b_3, d_6, c_4