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