Polyhedra: ⁦faces, edges, vertices⁩

⁦From the Ukrainian Grade 10 textbook (algebra and calculus with geometry)⁩, §⁦4, item 28⁩ '⁦Solid figures⁩. ⁦First facts about polyhedra⁩'. ⁦The surface of a polyhedron is made of polygons, called its faces⁩. ⁦The sides of the polygons are the edges of the polyhedron and their vertices are the vertices of the polyhedron⁩.

⁦The pyramid FABCDE has the base ABCDE and one apex F shared by all its side faces⁩. ⁦The side faces are triangles; the edges FA, FB, FC, FD and FE are the side edges and AB, BC, CD, DE and EA are the edges of the base⁩. ⁦A triangular pyramid DABC is also called a tetrahedron⁩.

⁦The prism ABCA₁B₁C₁ has two bases, the equal triangles ABC and A₁B₁C₁; its other faces are parallelograms, the side faces⁩. ⁦The edges AA₁, BB₁ and CC₁ are the side edges⁩. ⁦A four-sided prism whose base is a parallelogram is called a parallelepiped; if all its faces are rectangles it is a cuboid, and if all are squares, a cube⁩.

⁦You can turn the figure⁩. ⁦To choose faces, tap them or use the buttons in the list under the picture⁩.