Point Names an exact location in space
Line Segment Part of a line. It has two endpoints.
Endpoint The points at either end of the line segment.
Line A straight path of points that continues without end in both directions.
Ray A part of a line that has one endpoint and continues without end in one direction.
Plane A flat surface that continues without end in all directions.
Angle Two rays or line segments with the same endpoint.
Right Angle Measures 90 degrees and makes a square corner.
Acute Angle Measures less than 90 degrees.
Obtuse Angle Measure more than 90 degrees.
Intersecting Lines Lines that cross each other at exactly one point and form four angles.
Parallel Lines Lines that never intersect and are always the same distance apart.
Perpendicular Lines Line that intersect to form four right angles.
Dimension A measurement along a straight line of length, width, or height of a figure.
One-Dimensional A measure in only one direction, such as length.
Two-Dimensional A measure in two directions, such as length and width. A rectangle is an example.
Polygon A closed figure formed by 3 or more straight sides that are line segments
and intersect at the endpoints.
Triangle A polygon with 3 sides and 3 angles
Quadrilateral A polygon with 4 sides and 4 angles.
Pentagon A polygon with 5 sides and 5 angles.
Hexagon A polygon with 6 sides and 6 angles.
Octagon A polygon with 8 sides and 8 angles.
Decagon A polygon with 10 sides and 10 angles.
Parallelogram A quadrilateral with 2 pairs of parallel sides and opposite sides are equal.
Trapezoid A quadrilateral with exactly 1 pair of parallel sides
Rectangle A quadrilateral with 2 pairs of parallel sides and opposite sides equal
4 right angles.
Rhombus A quadrilateral with 2 pairs of parallel sides and 4 equal sides.
Square A quadrilateral with 2 pairs of parallel sides, 4 equal sides, and 4 right angles.
Congruent Figures that have the same shape and size
Transformation Any movement of a figure
Translation A figure slides to a new position along a straight line going up,
down, left, right, or diagonally
Rotation A figure moves to a new position by turning the figure around a point
Reflection A figure moves to a new position by flipping the figure over a line
Line Symmetry A figure that can be folded on a line so that the two parts match exactly