How can we help?

You can also find more resources in our Help Center.

Geometry Chapter 1 Vocabulary

STUDY
PLAY
conjecture
an unproven statement that is based on observations
point
has no dimension. usually represented by a small dot
line
extends in one dimension. usually represented by a straight line with two arrowheads to indicate that the line extends without end in two directions
plane
extends in two dimensions. usually represented by a shape that looks like a tabletop or wall
line segment
part of a line that consists of two endpoints and all points on the line that are between the endpoints
ray
part of a line that consists of an initial point and all points on the line that extend in one direction
initial point
the starting point of a ray
postulate
rules that are accepted without proof. also called axioms
congruent segments
segments that have the same length
congruent angles
angles that have the same measure
acute angle
an angle with measure between 0 and 90 degrees
obtuse angle
an angle with the measure between 90 and 180 degrees
right angle
an angle with measure equal to 90 degrees
straight angle
an angle with measure equal to 180 degrees
segment bisector
a segment, ray, line, or plane that intersects a segment at its midpoint
angle bisector
a ray that divides an angle into two adjacent angles that are congruent
vertical angles
two angles whose sides form two pairs of opposite rays
complementary angles
two angles whose measures have the sum of 90 degrees
supplementary angles
two angles whose measures have the sum of 180 degrees