The third has a triangular cross-section. (Sometimes the ‘cross-section’ is called the 'base'.) The distance between the two ends of the prism is always called the height of the prism even if ...

This may be shown by a net of the prism. Image caption, First work out the area of the triangular faces. The area of a triangle is ½ × base × height. There are two congruent (identical ...