Create an account
Unique angle assumption
Given any ray BC and a real number r between 0 and 180, there is a unique angle ABC on each side of BC such that m∠ABC = r
Equal angle measures Theorem
If two angles have the same measure, their complements have the same measure. If two angles have the same measure, their supplements have the same measure.
Multiplication property of inequality
If a < b and c > 0, then ac < bc. If a < b and c < 0, then ac > bc
Corresponding angles postulate
If two corresponding angles have the same measure, then the lines are parallel. If the lines are parallel, then corresponding angles have the same measure.
Parallel lines and slopes theorem
Two nonvertical lines are parallel if and only if they have the same slope
Transitivity of parallelism theorem
If line l is parallel to line m and lin m is parallel to line n, then line l is parallel to line n
Sk Theorem 1: size property
Under a size change Sk, the line through any two preimage points is parallel to the line through their images
Two perpendiculars theorem
If two coplanar lines l and m are each perpendicular to the same line, then they are parallel to each other
Perpendicular to parallels theorem
In a plane, if a line is perpendicular to one of the two parallel lines, then it is also perpendicular to the other
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!Reload
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