Geometry serves as the foundational language of the physical world, a profound mathematical lens through which we comprehend shapes, structures, and spatial relationships. From the elegance of symmetrical patterns to the intricacy of geometric forms, geometry stands as an indispensable tool, shaping both our intellect and the tangible world we inhabit.
Regular 2D Shapes
2D shapes have 2 dimensions and they can be measured by their length and width or length and height. Shapes that are in 2D are completely flat. Thus, they cannot be physically held, because they have no depth.
A paper is the best example of 2D Shapes. It has only height and width. A circle is also a 2D shape, but a circle has a curved edge. Since the circumference of the circle is equidistant from the centre, we measure it using the two parameters centre and diameter or radius.
| 2D Shape Name | 2D Shapes Properties | 3D Shape Equivalent |
|---|---|---|
| Circle | Circle is a shape created from curved lines. The curving line’s points are all equally spaced from the origin. Circles are entirely round. | Sphere |
| Equilateral Triangle | A shape with three sides. Triangles come in a variety of shapes. An equilateral triangle, which has three equal sides and three equal angles, serves as an illustration. 3 equal sides. 3 equal angles. | Pyramid or Prism (tetrahedron) |
| Square | A shape with four sides of equal length and four 90˚ angles. 4 equal sides. 4 equal angles. | Cube |
| Pentagon | A shape with five sides and five equal angles. | Dodecahedron |
| Deltoid | A quadrilateral with two pairs of sides of the same length. | – |
| Diamond | A quadrilateral with both pairs of opposite sides parallel and all sides of the same length. Unlike a square, however, its angles are not all 90˚. | Rhombohedron |
| Octagon | A shape with 8 equal sides. | – |
Irregular 2D Shapes
On the other hand, an irregular shape has sides of different lengths and angles of different sizes.Irregular shapes are shapes where the sides and interior angles are not all the same. They can be harder for children to identify, as they don't look like the conventional shape they are used to seeing when they are initially introduced to shapes.
An irregular shape is a shape which has sides and angles of any length and size. Examples of irregular 2D shapes:
| 2D Shape Name | 2D Shapes Properties | 3D Shape Equivalent |
|---|---|---|
| Ellipse | A closed curve that is similar to a circle but appears to have been 'stretched'. | Ovoid |
| Trapeze | A quadrilateral that has at least one pair of parallel sides. The parallel sides are called the bases of the trapezoid. | |
| Rectangle | Opposite sides are equal and all angles are right. | Cuboid |
| Scalene Triangle | All sides and angles have different lengths and measurements. | |
| Isosceles Triangle | Two sides and two angles have equal measures. |
