[list][*][b][u]Cross-Section[/u][/b]: a surface or shape that is or would be exposed by making a straight cut through something, especially at right angles to an axis.[br][/*][*][b][u]Solid of Revolution[/u][/b]: a three-dimensional figure obtained by rotating a two-dimensional figure (or curve) around a straight line (called the axis) that lies in the same plane.[br][/*][*][b][u]Axis of Rotation[/u][/b]: the straight line through all fixed points of a rotating rigid body around which all other points of the body move in circles. In this activity, this may be an arbitrary line, or the x-, y-, or z-axis.[br][/*][*][b][u]Space Figures[/u][/b]: Three-dimensional figures that have depth, width, and height.[/*][*][b][u]Polyhedron[/u][/b]: a three-dimensional figure whose surfaces are polygons.[/*][*][b][u]3D Projections[/u][/b]: a technique used to display three-dimensional objects on a two-dimensional surface which relies on perspective and aspect analysis. [/*][*][b][u]Perspective[/u][/b]: (1) the art and mathematics of realistically depicting three-dimensional objects in a two-dimensional plane. (2) the angle or direction in which a person looks at an object[/*][/list]