- Define the three dimensions of length, width, and height.
- Define and identify collinear points and coplanar points and lines.
- Identify objects that are zero-, one-, two-, and three-dimensional.
- Relate the concept of infinity to one-, two-, and three-dimensional objects.
- Infinite – having no boundary or limit.
- Collinear – lying in a straight line. Three or more points are collinear if a straight line can be drawn through all of them.
- Plane – a flat surface that extends forever in all directions (infinite). A plane has no thickness, so it has only two dimensions (length and width).
- Coplanar – lying in the same plane. Four or more points are coplanar if there is a plane that contains all of them.
- Zero-Dimensional – having no length, width, or height (ex. points)
- One-Dimensional – having length but no width or height (ex. lines, line segments, rays)
- one-dimensional with infinite length: lines and rays
- one-dimensional with measurable length: line segments
- Two-Dimensional – having length and width but no height (ex. planes / flat surfaces you can’t pick up)
- Three-Dimensional – having length, width, and height (ex. solids, geometric space, our world, things you can grab and hold)