a skilled carpenter carefully measures and cuts wooden boards on his workbench. Each board displays a clear four-sided shape with perfectly straight edges and right angles at every corner. The carpenter uses a square tool to check that each corner forms a perfect ninety-degree angle. As he works, the rectangular boards stack neatly because their parallel sides fit together perfectly. His apprentice organizes similar four-sided wooden pieces nearby, all showing the same geometric properties. The workshop contains windows, door frames, and table surfaces that all share this same four-cornered shape. having the shape of a rectangle with four sides and four right angles