Two-dimensional (2D) shapes are completely flat. They cannot be picked up. A polygon is a 2D shape with straight sides that meet at vertices. Polygons have names that show the number of sides they ...
Up until about two decades ago, all mammograms were done using an X-ray machine, which generated two-dimensional (2D) images of breast tissue. In 2011, however, the U.S. Food and Drug Administration ...