A quadrangular pyramid has five vertices. A quadrangular pyramid refers to a spatial closed figure composed of four triangles and a quadrilateral, while a regular quadrangular pyramid is an isosceles triangle with a square bottom and four triangles as congruent triangles.

Triangle is a closed figure composed of three line segments on the same plane but not on the same straight line, which has applications in mathematics and architecture. Ordinary triangles are divided into ordinary triangles (three sides are unequal) and isosceles triangles (isosceles triangles with unequal waist and equal waist and bottom).