相似长方体的边长、表面积与体积比例关系可视化
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所属专题
Similar Solids
该范例通过两个相似长方体的并置与缩放展示:当线性尺寸按比例缩放时,表面积按比例平方、体积按比例立方变化。核心数学概念包括相似几何、比例系数(dilation/k)、立体几何中的表面积与体积关系,以及由相似变换得到的尺度律。作图要点:使用 GeoGebra 的 Polygon 绘制长方体底面多边形轮廓与侧面边界,Prism 生成长方体实体;通过 Dilate 对对应长方体进行同比例缩放;用 Segment、Point 定义关键长度与参考点;再结合 Vector、Rotate 完成空间定位与面法向/旋转对齐;并用 Prism 的各面对象(如 faceABFE、faceBCGF、faceCDHG、faceADHE、faceEFGH)及边对象(edgeAE、edgeBF、edgeCG、edgeDH、edgeEF、edgeFG、edgeGH、edgeEH)组织可视化,进一步得到缩放前后对应的点 A、B、C、D、E 等与 A'、B'、C'、D'、E'。适合中学高年级至大学预备课程,用于立体几何、相似变换与比例尺度律的直观教学与探究。
GeoGebra 命令及参数
Polygon(A, B, C, D) → poly1, a, b, c, dPrism(poly1, E) → e, F, edgeBF, edgeCG, edgeDH, edgeEF, edgeFG, edgeGH, edgeEH, G, H, faceABFE, faceBCGF, faceCDHG, faceADHE, faceEFGH, edgeAEDilate(A, k, L) → A'Polygon(A', B', C', D') → poly2, a', b', c', d'Prism(poly2, E') → f, F', edgeB'I, edgeC'J, edgeD'K, edgeE'I, edgeIJ, edgeJK, edgeE'K, G', H', faceA'B'IE', faceB'C'JI, faceC'D'KJ, faceA'D'KE', faceE'IJK, edgeA'E'Segment(I, J) → gPoint(g) → KRotate(faceABFE, (t * 90°), a) → faceABFE'Rotate(faceBCGF, (t * 90°), b) → faceBCGF'Rotate(faceCDHG, (t * 90°), c) → faceCDHG'Rotate(faceADHE, (t * 90°), d) → faceADHE'Rotate(E, (t * 90°), a) → E'_1Rotate(F, (t * 90°), a) → F'_1Rotate(Rotate[faceEFGH, (t * 90°), a], (t * 90°), Segment[E'_1, F'_1]) → poly3Rotate(faceA'B'IE', (t * 90°), a') → faceA'B'IE''Rotate(faceB'C'JI, (t * 90°), b') → faceB'C'JI'Rotate(faceC'D'KJ, (t * 90°), c') → faceC'D'KJ'Rotate(faceA'D'KE', (t * 90°), d') → faceA'D'KE''Rotate(E', (t * 90°), a') → E''Rotate(F', (t * 90°), a') → F''Rotate(Rotate[faceE'IJK, (t * 90°), a'], (t * 90°), Segment[E'', F'']) → poly4Rotate(Segment[Midpoint[B', C'], Midpoint[F', G']], (t * 90°), b') → jRotate(Segment[Midpoint[B', F'], Midpoint[C', G']], (t * 90°), b') → iRotate(Segment[Midpoint[A', B'], Midpoint[E', F']], (t * 90°), a') → mRotate(Segment[Midpoint[A', E'], Midpoint[B', F']], (t * 90°), a') → nRotate(Segment[Midpoint[C', D'], Midpoint[G', H']], (t * 90°), c') → pRotate(Segment[Midpoint[C', G'], Midpoint[D', H']], (t * 90°), c') → qRotate(Segment[Midpoint[A', E'], Midpoint[D', H']], (t * 90°), d') → rRotate(Segment[Midpoint[A', D'], Midpoint[E', H']], (t * 90°), d') → sRotate(Rotate[Segment[Midpoint[E', F'], Midpoint[G', H']], (t * 90°), a'], (t * 90°), Segment[E'', F'']) → a_1Rotate(Rotate[Segment[Midpoint[E', H'], Midpoint[G', F']], (t * 90°), a'], (t * 90°), Segment[E'', F'']) → b_1Segment(Midpoint[A', B'], Midpoint[C', D']) → c_1Segment(Midpoint[A', D'], Midpoint[C', B']) → d_1Segment(Midpoint[F', C'], Midpoint[E', D']) → e_1Segment(Midpoint[F', A'], Midpoint[C', H']) → f_1Segment(L, E) → g_1Segment(L, H) → i_1Segment(L, F) → k_1Segment(L, G) → m_1Segment(H, H') → j_1Segment(G, G') → n_1Segment(E, E') → h_1Segment(F, F') → l_1Segment(L, A) → p_1Segment(A, A') → q_1Segment(L, B) → r_1Segment(B, B') → s_1Segment(L, C) → t_1Segment(C, C') → a_2Segment(L, D) → b_2Segment(D, D') → c_2Vector(E' + (0, 0, 0.3), E' + (0, 0, 1.3)) → uSegment(Midpoint[A', C'], Midpoint[E', G']) → d_2
AI 绘图提示语参考
绘制两个相似的长方体,其中一个长方体的边长是另一个的k倍。首先绘制一个底面为四边形ABCD的长方体,并添加顶点E。然后将点A沿直线L放大k倍得到A',并以此为底面绘制另一个长方体。接着围绕A'旋转底面四边形,生成旋转后的面。最后,围绕A'旋转边AE,生成旋转后的边,并连接相应的顶点,形成新的长方体。
以上提示语为根据原始绘图命令整理而来,仅供参考。