摘要或動機

In this study, we mainly explore the geometric construction in 3D. By conducting some problems about constructing circles, we define the PLC construction in 2D as constructing a circle, either passing through a given point (P), tangent to a given line (L) or tangent to a given circle (C). Besides, we aim to discuss the properties of the PLC construction and the relations between each other. We discover if we find a plane satisfying certain conditions in space, the properties in the PLC construction can apply to such a plane. Furthermore, we extend the properties in PLC to the PES construction in 3D, defined as constructing a sphere, either passing through a given point (P), tangent to a given plane (E) or tangent to a given sphere (S). Also we discuss the relations among them.這個研究主要在探討3D 的尺規實作。藉由歸納某些有關作圓的題目，我們定義2D 中的PLC作圖─作圓，過已知點（P）、切已知線（L）、切已知圓（C）。並探討PLC 作圖的性質及彼此的關聯性。而我們發現：在空間中只要找到滿足特定條件的平面，則2D 幾何作圖性質在該平面仍能沿用。此外，運用PLC 作圖性質，我們進一步推廣到空間中的PES 作圖─作球，過已知點（P）、切已知面（E）、切已知球（S），並探討各個類型間的關聯性。