lines
two lines that never touch
parallel
a 4 sided shape with equal sides
square
lines that cross, but do not form a right angle
intersecting
any 4 sided shape
quarilateral
lines that form a right angle when they cross
perpendicular
any closed, flat shape with straight side
polygon
an angle smaller than 900
acute
a 3 sided shape
traingle
a line thats larger than 900
obtuse
a 5 sided shape
pentagon