Geometry Vocab

Point

A position in space without length or width

Line

All points continuing in both directions that connect two unique points

Plane

All points in a 2D surface 

Collinear 

All points that share a line

Coplanar 

All points that share a plane (any 3 non-collinear points define on specific, unique plane)

Line segment

Portion of a line between 2 points inclusive of the 2 points

Midpoint

The point that divides a line segment equally into two parts

Bisect

To cut into equal pieces. A bisect or passes through the midpoint of the segment

Ray

All points from a starting point that continue in a direction endlessly

Angle

A ray with common end point

Opposite rays

Two rays that share an end point and form a line

Equality

Having equal measure

Congruency

Having the same shape

Right angle 

An angle that measures exactly 90 degrees 

obtuse angle 

An angle that is greater than 90 degrees and no over 180 degrees 

Acute angle

An angle measuring less than 90 degrees

Complementary angles

A set of 2 angles that share a line segment and add to 90 degrees exactly

Supplementary angles

2 angles that when placed & added together equal 180 degrees.

Linear pair

Supplementary angles with a shared side and shared endpoint

Vertical angles

A pair of angles form by intersecting lines that share a vertex but not sides

Equilateral polygon

A polygon with all sides congruent

Equiangular polygon

A polygon with all angles congruent

Regular polygon

An equilateral and equiangular polygon

Right triangle

Triangle with a right angle

Scalene triangle

Triangle where no sides are congruent

Equilateral triangle

Triangle with all sides of equal measure

Isosceles triangle

Triangle with at least 2 congruent sides

Circle

All points equidistant from a point

Center

The point that is equidistant from all the points on the circle

Radius

Distance from center to any point on the circle

Chord

A line segment with endpoints on the circle

Diameter

A chord that passes through the center of the circle

Tangent

A line segment with exactly one point on the circle and that point is perpendicular to the radius

circumcenter circle

Same center but different radii

Congruent circle

Same radius but different center

Rigid transformation

Maintains shape and size

Non rigid transformation

Maintains shape but not size

Inductive reasoning

the process of observing data, recognizing a pattern, and making generalizations about those patterns. The outcome is a conjecture

Deductive reasoning

Starting with a premise and use only logical truths to prove a conclusion.