21 terms

Area

The number of square units needed to fill up a region on a flat surface

base

(1) Of a triangle: any side of a triangle to which a height is drawn.

(2) Of a trapezoid: either of the two parallel sides.

(3) Of a parallelogram (including rectangle, rhombus, and square): any side to which a height is drawn.

(2) Of a trapezoid: either of the two parallel sides.

(3) Of a parallelogram (including rectangle, rhombus, and square): any side to which a height is drawn.

circumference

The perimeter (distance around) of a circle.

cross section

The intersection of a three-dimensional solid and a plane.

degree

A unit for measuring angles. Usually denoted by °

diameter

A line segment drawn through the center of a circle with both endpoints on the circle.

edge

In three dimensions, a line segment formed by the intersection of two faces of a polyhedron.

face

One of the flat surfaces of a polyhedron, including the base(s).

inference

A statistical prediction.

irrational number

The set of numbers that cannot be expressed in the form a/b, where a and b are integers and b ≠ 0. For example, π and √2

lateral faces

The (flat) side of a polyhedron. It is always a polygon.

measurement

An indication of the size or magnitude of a geometric figure.

polygon

A two-dimensional closed figure of three or more line segments (sides) connected end to end. Each segment is a side and only intersects the endpoints of its two adjacent sides. Each point of intersection is a vertex.

polyhedron

A three-dimensional figure with no holes for which all faces are polygons.

pi (π)

The ratio of the circumference (C) of the circle to its diameter (d).

pyramid

A three-dimensional figure with a base that is a polygon. The lateral faces are formed by connecting each vertex of the base to a single point (the vertex of the pyramid) that is above or below the surface that contains the base.

right rectangular prism

A three-dimensional figure that consists of two parallel congruent polygons (called bases) and a vertical surface containing segments connecting each point on each side of one base to the corresponding point on the other base. The lateral surface of a prism consists of parallelograms.

surface area

The sum of all the area(s) of the surface(s) of a three-dimensional solid.

vertex

(1) For a two-dimensional geometric shape: a point where two or more line segments or rays meet to form a "corner," such as in a polygon or angle.

(2) For a three-dimensional polyhedron: a point where the edges of the solid meet.

(2) For a three-dimensional polyhedron: a point where the edges of the solid meet.

volume

A measurement of the size of the three-dimensional region enclosed within an object.

chord

A segment whose endpoints both lie on the circle.