Vocab 1
Bases
The surface of a polygon that is touching the ground, and the opposite parallel face.
Diameter
The distance across a circle through its center.
Pi
The ratio of the circumference of a circle to the diameter of the circle. Approximations for pi are 3.14.
Radius
The distance from the center to any point on the circle.
Surface area
The sum of the areas of all surfaces (faces) of a 3-dimensional figure.
Circumfrance
The distance around a circle.
Edge
Where two planes intersect in a line.
Plane
A two dimensional flat surface that extends all directions and contains at least three no ncollinear points.
Skew lines
Lines that do not intersect and are not in the same plane.
Vertex
Where three or more planes intersect.
Composite figures
Figures made from two or more geometric figures.
Face
A flat surface, the side or base of a prism.
Polyhedron
A solid with all flat surfaces that are polygons.
Slant height
The length of the altitude of a lateral face of a regular pyramid or cone.
Volume
The measure of space occupied by a solid region.
Cone
A solid or hollow object which tapers from a circular or roughly circular base to a point.
Lateral area
The sum of the areas of the lateral faces of a solid.
Prism
A polyhedron that has two parallel congruent bases in the shape of polygons.
Solids
Three dimensional figures.
Scalene
All sides unequal in length.
Cylinder
A solid that has two parallel, congruent bases (usually circular) connected with a curved side.
Lateral face
All of the surfaces of the figure except for the base or bases.
Pyramid
A polyhedron that has a polygon for a base and triangles for sides.
Sphere
A set of all points in a space that are a given distance of r from the center.
When two sides of a triangle have equal length.