Geometry Vocabulary for Grade 9

Front

Point

Back

exact location in space with no size or dimension

Front

Line

Back

straight path extending infinitely in both directions with no thickness

Front

Plane

Back

flat surface that extends infinitely in all directions

Front

Segment

Back

of a line with two endpoints

Front

Ray

Back

of a line with one endpoint, extending infinitely in one direction

Front

Angle

Back

by two rays with a common endpoint

Front

Vertex

Back

common endpoint of two rays forming an angle

Front

Congruent Segments

Back

with equal length

Front

Congruent Angles

Back

with equal measure

Front

Complementary Angles

Back