A polygon is a flat, two-dimensional shape with straight sides that are all connected to form a closed figure. Polygons have at least three sides, and they cannot have curved sides. Examples include triangles, squares, and pentagons. To use three-part cards, match the labels to the corresponding pictures. Verify the matches using the control cards with the labels attached. This material includes three to ten-sided polygons: triangle, square, pentagon, hexagon, heptagon, octagon, nonagon, and dec