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[19] [20] Examples are square pyramid and pentagonal pyramid, a four- and five-triangular faces pyramid with a square and pentagon base, respectively; they are classified as the first and second Johnson solid if their regular faces and edges that are equal in length, and their symmetries are C 4v of order 8 and C 5v of order 10, respectively.
Its surface area is four times the area of an equilateral triangle: = =. [7] Its volume can be ascertained similarly as the other pyramids, one-third of the base times height. Because the base is an equilateral, it is: [ 7 ] V = 1 3 ⋅ ( 3 4 a 2 ) ⋅ 6 3 a = a 3 6 2 ≈ 0.118 a 3 . {\displaystyle V={\frac {1}{3}}\cdot \left({\frac {\sqrt {3 ...
An elongated triangular pyramid with edge length has a height, by adding the height of a regular tetrahedron and a triangular prism: [4] (+). Its surface area can be calculated by adding the area of all eight equilateral triangles and three squares: [2] (+), and its volume can be calculated by slicing it into a regular tetrahedron and a prism, adding their volume up: [2]: ((+)).
If the apex of the pyramid is directly above the center of the square, it is a right square pyramid with four isosceles triangles; otherwise, it is an oblique square pyramid. When all of the pyramid's edges are equal in length, its triangles are all equilateral. It is called an equilateral square pyramid, an example of a Johnson solid.
For a cube the lateral surface area would be the area of the four sides. If the edge of the cube has length a, the area of one square face A face = a ⋅ a = a 2. Thus the lateral surface of a cube will be the area of four faces: 4a 2. More generally, the lateral surface area of a prism is the sum of the areas of the sides of the prism. [1]
The surface area of a gyroelongated square bipyramid is 16 times the area of an equilateral triangle, that is: [4], and the volume of a gyroelongated square bipyramid is obtained by slicing it into two equilateral square pyramids and one square antiprism, and then adding their volume: [4] + +.
The square pyramid can be seen as a triangular prism where one of its side edges (joining two squares) is collapsed into a point, losing one edge and one vertex, and changing two squares into triangles. Geometric variations with irregular faces can also be constructed. Some irregular pentahedra with six vertices may be called wedges.
The dihedral angle of an augmented triangular prism between square and triangle is the dihedral angle of a triangular prism between the base and its lateral face, / = The dihedral angle of an equilateral square pyramid between a triangular face and its base is arctan ( 2 ) ≈ 54.7 ∘ {\textstyle \arctan \left({\sqrt {2}}\right)\approx 54. ...