math test
posted by brianna .
ok this past week i was sick 4 2 days and i need 2 finish this math test by today!!!! and i didn't get 2 learn anything like u know, not practive soo plz anwser these questions: 1.what is a concave polygon 2.what are concentric cicles? 3. what does this mean: a polygon that is CONGRENT to the one shown below there is a square below the words and srry about this but wut does perpendicular mean again? thank you!!!!!!!

In geometry, two lines or planes (or a line and a plane) are considered perpendicular

http://www.mathopenref.com/polygonconcave.html
http://www.mathopenref.com/concentric.html
http://www.mathopenref.com/congruentpolygons.html