The theorems, formulas and principles in plane geometry reveal the intrinsic relations and basic laws of geometrical concepts.
平面几何的定理、公式、法则反映了几何概念的内在联系，揭示了它们之间的基本规律。
2
This paper describes the method of the directional plane, an effective method to realize the geometrical construction.
本文介绍了实现几何构型的一个行之有效的方法——有向平面法。
3
From the theory of light diffraction and geometrical optics, aperture diffraction near the focal plane of microscope objectives and imaging on the image plane are studied.