D15 Flashcards
Polyhedron
A 3-D solid made entirely by polygons
Face
A flat surface that makes up part of a 3D figure
Edge
A segment formed by the intersection of 3 or more faces
Vertex
A point formed by the intersection of 3 or more faces
Are cylinders, spheres, or cones considered polyhedrons ?
Nope
Polyhedrons are classified by
The number of faces
Regular polyhedron
A polyhedron made of congruent regular polygons
There are 5 regular polyhedrons ; these are known as the
Platonic solids
( Tetrahedron, cube, octahedron, dodecahedron, isosohedron)
Two types of special polyhedrons are
Prims and pyramids
Has two faces called bases that are congruent, parallel polygons.
Prism
The other faces of the polyhedron, called ____ ___ , are parallelograms that connect the corresponding sides of the bases
Later faces
The later faces meet to form the
Lateral edges
Prisms are classified by their
Bases
The ____ of a prism is the length of ita altitude, any perpendicular segment from one base to the plane of the other base
Height
A prism whose lateral faces are rectangles is called a
Right prism
It’s lateral edges are _____ to it’s bases
Perpendicular
A prism that is not a right prism is called an
Oblique prism
Has only one polygonal base. The other faces of the polyhedron, called lateral faces, are triangles that meet to form the lateral edges.
Pyramid
A pyramid whose base is a regular polygon is called a
Regular pyramid.
The later faces of a ___ ___ are congruent, isosceles triangles
Regular pyramids
The height of each triangular lateral faces is called the ___ ___ of the pyramid
Slant height
The radius of the cylinder is the ___ of the base
Radius
The segment connecting the centers of the base is called the
Axis
Is half a sphere and it’s circular base
Hemisphere
The circle that encloses the base of a hemisphere is called the ___ ___ of a sphere
Great circle
Is the digram of the surfaces of the three-dimensional figure that can be folded to form the three -dimensional figure
Net
Is the intersection of a three-dimensional figure and a plane
Cross section
Prism
Number of faces
N+2
Prism
Number of vertices
2n
Prism
Number of edges
3n
Pyramid
Number of faces
N+1
Pyramid
Number of vertices
N+1
Pyramid
Number of edges
2n
Euler’s formula
For any convex polyhedron, the number of faces, F, vertices, V, and edges, E, are related by the formula
F+V=E+2
