A prismatoid having polygons with the same number of sides as bases, and faces that are parallelograms or trapezoids.

四个相等平行四形；角等平行四形。

Stress shielding effect of the trihedral fix trough plate,trapezoid compression plate and Tianjin compression plate on the long bone measured with the electrical measuring method.

用电测法测量了三种股骨中段骨折内固定钢板（三面固定槽形板、梯形板、天津板）固定后对骨应力遮挡效应。

Ends of the tegular filters (10) are cut off crosswise to make the end surfaces respectively form inclined surfaces such that vertical sections of the tegular filters (10) are in a rough trapezoid.

瓦状滤波器(10)端部被斜向切除以使端面分别形成斜面，从而瓦状滤波器(10)垂截面呈大致梯形。