Geometry Fundamentals Vocabulary

Vocabulary review flashcards defining fundamental geometry terms, angles, polygon classifications, and line properties from the lecture.

Point

A geometric concept that has no dimension and is represented by a dot.

Line

A geometric figure with one dimension that is represented by a line with two arrows.

Plane

A geometric surface with two dimensions represented by a shape that looks like a floor or wall.

Collinear points

Points that lie on the same line.

Coplanar points

Points that lie on the same plane.

Line segments

Parts of a line consisting of two points, called endpoints, and all the points on the line between those endpoints.

Ray

Consists of endpoint $a$ and all points through $b$.

Opposite rays

Rays that have the same endpoint on a line but go in opposite directions.

Intersection

The spot where two or more geometric figures share points.

Postulate (Axiom)

A rule that is accepted without proof.

Theorem

A rule that can be proved.

Coordinate

The real number that corresponds to a point.

Distance

The absolute value of the difference of the coordinates of two points.

Congruent segments

Line segments that have the same length.

Sides of a polygon

The line segments that form the polygon.

Vertex of a polygon

An endpoint of the sides of the polygon.

Convex

A polygon property where if the sides are extended into lines, no lines pass through the interior of the polygon.

Concave

The opposite of convex, where a line through a side goes through the interior of the polygon.

N-gon

A polygon with $n$ sides.

Equilateral

A polygon in which all of its sides are congruent.

Equiangular

A polygon in which all of its interior angles are congruent.

Angle

Consists of two different rays with the same endpoint.

Sides of an angle

The rays or points that form the angle.

Vertex of an angle

The common endpoint of the rays forming the angle.

Measure of an angle

An angle measurement that can be between $0^\text{o}$ and $180^\text{o}$.

Acute angle

An angle with a measure between $0^\text{o}$ and $90^\text{o}$.

Right angle

An angle with a measure of $90^\text{o}$.

Obtuse angle

An angle with a measure between $90^\text{o}$ and $100^\text{o}$.

Congruent angles

Angles that have the same measure.

Angle bisector

A ray that divides an angle into two angles that are congruent.

Complementary angles

Two angles whose sum is $90^\text{o}$.

Supplementary angles

Two angles whose sum is $180^\text{o}$.

Adjacent angles

Two angles that share a common vertex and side but have no common interior points.

Linear pair

Two adjacent angles whose non-common sides are opposite rays.

Vertical angles

Two angles formed by two intersecting lines and positioned opposite of each other.