**TI83F* AppVariable file 03/27/09, 16:32 GLPA05nav AEC13267AEFC43F88E67E1C0E88B5B83GLPA05.GLPA051  area]area:The number of square units needed to cover a surface enclosed by a geometric figure.  formula formula:An equation that states a rule for the relationship between certain quantities. Example: A = r is the formula for finding the area of a circle.   identity Kidentity:An equation that is true for every value of the variable.   inequality binequality:An open sentence that uses the symbol <, , > or  to compare two quantities.  null Set or empty Set null Set or empty Set:Some equations have no solution.When this occurs, the solution is the null or empty set and is shown by the symbol or { }.   perimeter T!>perimeter:The distance around a closed geometric figure. 8`  b 0@@ `!@@B@@  0` 0`  0@ @ 8"!%HR#a 9&@||!$C ҩ@ AQJ