1. A perpendicular bisector of a chord passes through the centre and bisects the arc. 弦的垂直平分线经过圆心，并且平分弦所对的两条弧。
2. In effect, the side cast is simply the overhead or perpendicular cast with the rod traveling in a horizontal plane. 投在生效的侧，侧演员是只需架空或垂直演员在一个水准的飞机旅行的杆。
3. The angle drawn at the point of incidence (intersection of) a reflected ray and the normal line perpendicular to the reflecting surface. 中义光线在物体表面的投射点上反射出来的光线与物体表面垂直法线所夹的角度。
英英解释
n.
1. a straight line at right angles to another line
2. a Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered
3. a cord from which a metal weight is suspended pointing directly to the earth's center of gravity; us
4. an extremely steep face adj.
1. intersecting at or forming right angles
2. at right angles to the plane of the horizon or a base line
3. extremely steep
