MATHO

Geometry Vocabulary

A part of a line that starts at an endpoint and extends forever

in one direction.

A quadrilateral with four right angles.

A triangle with no congruent sides.

A quadrilateral with four congruent sides and four right

angles.

Two angles in the same plane with a common vertex and a

common side, but no common interior points.

1 2

1 & 2 are adjacent angles

Points that lie on the same line.

A R M

A, R, & M are collinear points

To divide into two congruent parts.

L

K

M

𝑱𝑲 bisects LJM

J

A corner or point where lines, rays, polygons, or other geometric figures meet.

vertex

A figure formed by two rays with a common endpoint.

TAR

T A

R

An undefined term: has a straight path that has no

thickness and extends forever.

H I

𝑯𝑰

Part of a line consisting of two endpoints and all points

between them.

J K

𝑱𝑲

Lines in the same plane that do not intersect.

W E

G O

𝑾𝑬 𝑮𝑶

Lines that intersect at 90 angles.

M

E

𝑴 ⊥ 𝑬

A closed plane figure formed by three or more segments such that each segment

intersects exactly two other segments only at their endpoints and no two segments with a common endpoint are collinear.

A four-sided polygon.

Angles that have the same measure

B

E

B ≅ 𝑬

Two segments that have the same length.

O K

Y A

𝑶𝑲 ≅ 𝒀𝑨

A polygon that is both equilateral and equiangular.

Points that lie in the same plane.

A polygon that is not regular.

The point that divides a segment into two congruent segments.

O B C

O is the midpoint of 𝑪𝑩

Have the same shape but not necessarily the same size.

3

4 5

6

8 10