Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account



a series of points that extend in opposite directions without end.


a part of a line with one endpoint and all points of the line on one side of the endpoint.


a part of a line with two endpoints and all points in between.


a flat surface that extends indefinitely in all directions and has no thickness.

intersecting lines

lie in the same plane and have exactly one point in common.

parallel lines

lines in the same plane that never intersect.

skew lines

lie in different planes and are neither parallel nor intersecting.


is a figure formed by two rays with a common endpoint.


the point of intersection of two sides of an angle or figure.


a location in space that has no size

acute angle

an angle less than 90 degrees but more than 0 degrees

obtuse angle

an angle between 90 and 180 degrees

right angle

an angle that measures 90 degrees

straight angle

an angle of 180 degrees

complementary angles

Two angles whose sum is 90 degrees

supplementary angles

Two angles whose sum is 180 degrees

adjacent angles

are a pair of angles with a common vertex and a common side, but no common interior points

vertical angles

opposite angles formed by two intersecting lines

congruent angles

angles that have equal measures

congruent sides

sides that have the same length.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording