Geometric figures are shapes that can be described using mathematics. A RHOMBUS is a four-sided figure with all sides equal in length and opposite sides parallel. AREA is the measure of the two-dimensional space enclosed by a shape. A TRIANGLE is a three-sided figure with three straight sides and three angles. A polygon is a closed two-dimensional figure with three or more sides. An OBLONG is a four-sided figure with two pairs of parallel sides and unequal lengths. A SPHERE is a three-dimensional figure with all points on its surface equidistant from its center. A CONE is a three-dimensional figure with a circular base and a curved side. A PRISM is a three-dimensional figure with two parallel faces and other faces that are parallelograms. A SOLID is a three-dimensional figure with length, width, and height. A SQUARE is a four-sided figure with all sides equal in length and all angles right angles. An apothem is a line segment from the center of a regular polygon to the midpoint of one of its sides. An ELLIPSE is a two-dimensional figure with two focal points and all points on its circumference equidistant from its foci. A hexagon is a six-sided figure with six equal sides and six angles. A nonagon is a nine-sided figure with nine equal sides and nine angles. A pentagon is a five-sided figure with five equal sides and five angles.