adjacent
angles that share a side and a vertex
bisect
to divide into two congruent parts
circumference
the distance around the circle (equal to pi times diameter)
coincide
to occupy the same position
congruent
having exactly the same size and shape
coordinate
the number associated with a point on a number line
diagonal
a segment that joins two nonconsecutive vertices of a polygon
diameter
a line segment that passes through the center of a circle & has endpoints on the circumference of the circle
equivalent
two things that are equal
hexagon
a polygon with 6 sides
hypotenuse
in a right triangle, the side opposite the right angle
intersecting lines
lines that meet and cross over at one point
line of symmetry
a line that divides a figure into two halves that are mirror images of each other
octagon
a polygon with 8 sides
origin
on a number line, zero; in a coordinate plane, the point (0,0)
parallel
two lines that are everywhere the same distance apart and never intersect
parallelogram
a quadrilateral in which both pairs of opposite sides are parallel
pentagon
a polygon with 5 sides
perimeter
the sum of the lengths of the sides of a polygon
perpendicular
intersecting at right angles
pi
approximately 3.1416, ratio of the circumference to the diameter of the circle
quadrilateral
a polygon with 4 sides
radius
a line segment with one endpoint at the center of a circle and the other endpoint on the circumference
similar
having the same shape, but possibly a different size
translation
a transformation that slides a figure from one position to another (slide)
transversal
a line intersecting two or more lines
trapezoid
a quadrilateral with only one pair of parallel sides
volume
the amount of space an object takes up, usually expressed in cubic units