point

an exact location in space

line

an endless collection of points along a straight path

line segment

part of a line that has two endpoints

ray

part of a line that has one endpoint and extends endlessly in the other direction

plane

an endless, flat surface that is named by any three points not on the same line

angle

two rays that have the same endpoint

vertex

the endpoint of a ray

right angle

an angle that measures exactly 90 degrees

straight angle

an angle that measures exactly 180 degrees

acute angle

an angle that is less than 90 degrees

obtuse angle

an angle that is more than 90 degrees and less than 180 degrees

degrees

what we measure angles in