Most children know the names of basic two-dimensional shapes before they enter school. Squares, triangles, and circles are easy for young children to recognize even if they can’t count very high. As they get older they can discern more differences among shapes and learn more precise words for the variety of geometric shapes they encounter. Though the list of names of shapes can seem daunting, they are much easier to learn if you have visual aids.
Flat (Two-Dimensional) Figures with Curves
Circle – A circle is a closed curve with constant curvature. The distance from the center to the border is constant, no matter where the point is on the border. Technically speaking, a “circle” refers to the curved boundary, while a “disk” is a circle plus its interior. In everyday life, the two terms can be used interchangeably.
Ellipse – An ellipse is a circle squished (or stretched) in one direction. If you cut a cone or a cylinder at an angle, the cross-section is an ellipse. An ellipse has two foci with the following property: For any triangle you draw that connects the two foci and an arbitrary point on the ellipse’s border, the perimeter of the triangle is constant. A circle is a special type of ellipse in which the two foci coincide at the same point.
Stadium – A stadium is an oblong figure formed by joining semicircles to opposite ends of a rectangle. It gets its name from the shape of sport fields.
Oval – An oval is a non-specific term for any sort of closed oblong or egg-shaped curve without points. It includes ellipses, stadiums, and more irregular egg-shaped curves.
Arch – An arch is a shape with one curved arc opposite a straight edge. It may have more than one straight side.
Circular Sector – A circular sector is a wedge or pie slice cut from a circle. The vertex of a circular sector is the center of the circle from which it is cut.
Circular Segment – A circular segment is formed by cutting a circle along a chord. It is a two-sided shape, with one side curved and the other side straight. Arches can be shaped like circular segments
Lens – A lens is a two-sided figure formed from two arcs; both arcs are convex with respect to the interior of the figure. It has two vertices where the arcs meet.
Crescent – A crescent is a two-sided figure formed from two arcs; one curved side is convex with respect to the interior and the other is concave. It can be formed by taking a disk and removing a smaller disk along the edge.
Annulus – An annulus is a ring. It is formed by taking a disk and removing a smaller disk from the center.
Polygons
Triangle – A triangle is a three-sided figure. One property of triangles is that all three angles add up to 180 degrees. The longest side is opposite the largest angle, and the shortest side is opposite the smallest angle.
Scalene Triangle – A scalene triangle has three sides of unequal length. All three angles are also unequal.
Isosceles Triangle – A triangle with two sides of equal length and a third side that is either longer or shorter than the other two. Because two sides are equal, the angles opposite these sides are also equal.
Equilateral Triangle – A triangle with three equal sides and three equal angles. Also called an equiangular triangle, each of the angles is 60 degrees.
Obtuse Triangle – A triangle that has one angle with a measure greater than 90 degrees, aka an obtuse angle. The other two angles are necessarily less than 90 degrees.
Right Triangle – A triangle with one angle that is exactly 90 degrees, aka a right angle. The other two angles add up to 90 degrees.
Acute Triangle – A triangle whose three angles are all less than 90 degrees, aka acute angles.
More Geometry Resources
Related mathematics articles in drawing shapes and using geometric formulas:
List of Geometry Formulas for Angle, Length, Area, and Volume
Tracing Patterns for Star Shapes
Regular Polygon Tracing Patterns and Coloring Pages
Regular, Irregular, Equilateral, and Equiangular Polygons
Quadrilateral – Any four-sided figure with straight edges.
Parallelogram – A four sided figure that has two pairs of parallel sides. Opposite sides are equal in length, and opposite angles are equal as well.
Rectangle – A parallelogram with four right angles.
Rhombus – A parallelogram with four equal sides. See also, Rhombus Area Formula.
Trapezoid – A quadrilateral with one pair of parallel sides.
Kite – A quadrilateral with two pairs of sides that have equal length. The sides with equal length are adjacent to one another, rather than opposite as with a parallelogram.
Square – A rectangle that is also a rhombus. It has four equal sides and four equal angles with a measure of 90 degrees.
Pentagon – A pentagon is a five-sided polygon. A regular pentagon has five equal sides and five equal angles.
Hexagon – A hexagon is a six-sided polygon. See also, Regular Hexagon Area Formula.
Heptagon – A heptagon is a seven-sided polygon.
Octagon – An octagon is an eight-sided polygon. A stop sign is in the shape of a regular octagon since it has eight equal sides and eight equal angles.
Nonagon – A nonagon is a nine-sided polygon.
Decagon – A decagon is a ten-sided polygon.
Regular Polygon – Having equal side lengths and equal angles at the vertices.
Convex Polygon – All vertex angles as measured from the interior are less than 180 degrees. Equivalently, all vertex angles measured from the exterior or greater than 180 degrees.
Solid Shapes with Curved Surfaces
Sphere – A sphere is the three-dimensional analogue of a disk. The boundary of a sphere is a three-dimensional closed curved surface such that every point on the surface is equidistant from the center
Ellipsoid – The three-dimensional analogue of an ellipse, it can be thought of as a sphere that has been squished or stretched in one or two directions. If two of the three axes have equal length it is called a spheroid. See Ellipsoid Surface Area Formula.
Cone – A cone has a circular base that tapers linearly to a point, called the apex. If the tip is sliced off, the resulting shape is called a conical frustum.
Cylinder – A cylinder has two circular bases of equal size at the ends, and a middle section that can be formed by rolling a rectangle into a tube. It is the standard shape for canned foods. A conical frustum is like a cylinder except that the circular ends are different sizes.
Barrel – Like a cylinder, both ends of a barrel are circles of equal size. But unlike a cylinder, its sides do not go straight up and down, but rather bulge outward in the middle.
Torus – A torus is the technical mathematical term for a doughnut or bagel shape.
Dome – A dome is any solid shape that has a flat base and a curved surface connecting the boundary of the base. A hemisphere (sphere cut in two) is a type of dome, as is a spherical cap.
Polyhedra
Triangular Prism – A solid shape with two equal triangular faces on opposite ends oriented in the same direction and parallel. three parallelograms connect the matching triangular edges. If the parallelograms are rectangles, it is called a right prism. Otherwise it is called an oblique prism.
Rectangular Prism – A rectangular prism is a solid shape with six rectangular faces. Opposite faces have the same shape, size, and orientation and are parallel.
Cube – A regular rectangular prism; all faces are squares of equal size. It has six faces, eight vertices, 12 edges, and is one of the five Platonic solids.
Parallelepiped – A generalization of a rectangular prism in which all the faces are parallelograms, but not necessarily rectangles. A parallelepiped has six faces that come in parallel pairs.
Pentagonal Prism – A pentagonal prism has two equal pentagonal faces on opposite ends oriented in the same direction and parallel to one another. Five parallelogram faces connect the matching pentagonal edges.
Hexagonal Prism – A solid shape with two equal hexagonal faces on opposite ends oriented in the same direction and parallel. Six parallelogram faces connect the matching hexagonal edges.
Tetrahedron – Also called a triangular prism, this shape has four triangular faces, four vertices, and six edges. If the triangles are equilateral, it is a Platonic solid,
Square Pyramid – A pyramid with a square base and four triangular faces that meet at a point opposite to the square base.
Pentagonal Pyramid – A pyramid with a pentagonal base and five triangular faces that meet at a point opposite to the base.
Hexagonal Pyramid – A pyramid with a hexagonal base and six triangular faces that meet at a point opposite to the base.
Octahedron – A solid shape with eight triangular faces, six vertices, and 12 edges. Each vertex is the meeting point of four triangles. If the triangles are equilateral, it is one of the Platonic solids
Dodecahedron – Any solid shape with 12 faces. A pentagonal dodecahedron is a Platonic solid with 12 regular pentagonal faces, 20 vertices, and 30 edges, where each vertex is the meeting point of three pentagons. Not all dodecahedrons have pentagonal faces, for example, a rhombic dodecahedron’s 12 faces are rhombuses.
Icosahedron – A solid shape with 20 triangular faces, 12 vertices, and 30 edges. Each vertex is the meeting point of five triangles. If the triangles are equilateral, it is one of the Platonic solids.
More Math ResourcesFree M. C. Escher Lizard Tessellation Patterns (for creating website backgrounds or teaching tessellations)
How to Find the Area of a Parallelogram: 2 Different Methods
How to Write Numbers in English from 1 to 10,000
Number Properties Quiz for Middle School: Factors, Multiples, Primes, and More
All the drawings of two-dimensional shapes and polyhedra in this article (except the octahedron, icosahedron, dodecahedron, and rhombic dodecahedron) were created by the author. Transparent images of the octahedron, icosahedron, dodecahedron, and rhombic dodecahedron are courtesy of Wikimedia Commons. Pictures of other three-dimensional shapes are courtesy of free stock photo resources. You can create polygons in free programs such as MS Paint, Geogebra, GIMP, or with Pixlr.com, a free online image editing program.
, Names of Geometric Shapes — With Pictures www.ozeldersin.com bitirme tezi,ödev,proje dönem ödevi