congruent
two or more figures having exactly the same shape and size; coinciding when superimposed
coordinates
an ordered pair of numbersthat identifies a point on a coordinate plane written as (x,y)
line of symmetry
a line that divides a figure into two congruent halves that are mirror images of each other; a simple test to determine if an object has this is to fold the figure along the line and see if the two figures coincide