There are only a few geometric proofs for liberal arts in college entrance examination. (1) Prove that the straight line is parallel or perpendicular to the plane; (2) prove that the plane is parallel or vertical; (3) Find the volume of the geometry; (4) Find the relationship between the straight line and the plane. A it is rare to find that a straight line is parallel to a plane, just find that a straight line is parallel to a plane. The most common ones are structural triangles, in which the midline is found to be parallel to the third side or the parallel square is found, and the opposite sides are found to be parallel. B to find a straight line perpendicular, generally it is to find a straight line perpendicular to two intersecting straight lines on the plane. You can see if there are any hidden isosceles triangles or equilateral triangles in the topic. If there is, it will be much easier. C to find the plane parallel, as long as two intersecting straight lines in the plane are parallel at the same time, this topic is rare in the college entrance examination. There are many ways to find the perpendicularity between faces. First, find two intersecting straight lines in one plane, which are perpendicular to the other plane at the same time. Second: Find the dihedral angle of these two faces equal to 90. Third: find the straight line perpendicular to the intersection of these two surfaces in a plane, perpendicular to the other surface ... e It depends on the specific topic to find the volume of the geometry.