等值分数 by Jennifer Gomulka

几何画板及绘图内容加载中，请稍等……

2017-05-31 21:53

圆多边形几何作图

①本范例通过动态演示分数与饼图的关系，直观展示等值分数的几何意义；②涉及核心数学概念包括分数表示、几何图形分割、比例关系；③构造要点运用了Polygon（多边形）、If（条件判断）、orientation（方向）、frameSizeV/H（尺寸）、FramePt（框架点）、numerator/denominator（分子分母）、subdivisions（细分）等GeoGebra命令；④适合初中数学教学，用于帮助学生理解分数的基本性质和等值分数的判定方法。

GeoGebra 命令及参数

Polygon(FramePt, FramePt + (frameSizeH, 0), FramePt + (frameSizeH, frameSizeV), FramePt + (0, frameSizeV)) → Frame, d_1, a, b, c
If(orientation ≟ 1, Polygon[FramePt, FramePt + (frameSizeH, 0), FramePt + (frameSizeH, (numerator * frameSizeV / denominator)), FramePt + (0, (numerator * frameSizeV / denominator))], Polygon[FramePt, FramePt + ((numerator * frameSizeH / denominator), 0), FramePt + ((numerator * frameSizeH / denominator), frameSizeV), FramePt + (0, frameSizeV)]) → shadePoly
If(orientation ≟ 1, Sequence[Segment[FramePt + (0, i), FramePt + (frameSizeH, i)], i, 0, frameSizeV, frameSizeV / denominator], Sequence[Segment[FramePt + (i, 0), FramePt + (i, frameSizeV)], i, 0, frameSizeH, frameSizeH / denominator]) → div
If(orientation ≟ 2, Sequence[Segment[FramePt + (0, i), FramePt + (frameSizeH, i)], i, 0, frameSizeV, frameSizeV / subdivisions], Sequence[Segment[FramePt + (i, 0), FramePt + (i, frameSizeV)], i, 0, frameSizeH, frameSizeH / subdivisions]) → subdivDiv