2D shapes are plane figures that have length and width but no depth – they can only be measured in two dimensions. They are everywhere around us, from the screen you’re looking at to the books you read! Understanding 2D shapes is a crucial part of math and helps develop spatial awareness in kids.
What are 2D Shapes?
2D shapes, or two-dimensional shapes, are flat figures that have only two measurable dimensions: length and width. Unlike 3D shapes, they do not have depth or thickness. These shapes are contained within a plane, which is a flat surface extending in all directions, and can be drawn or represented on paper, screens, or any flat medium.
Examples of 2D Shapes are Circle, Square, Triangle, Rectangle, Pentagon, Hexagon, etc
Key Features of 2D Shapes
- Sides: The straight edges of a shape.
- Vertices (Corners): Points where two sides meet.
- Angles: The space between two sides measured in degrees. For example, squares and rectangles have right angles, which measure 90°.
Types of 2D Shapes
2D shapes can be classified as Regular and Irregular shapes, based on the measure of their sides and angles.
- Regular Shapes: Shapes where all sides and angles are equal. In a regular shape, every side has the same length, and every angle has the same measurement.
- Irregular Shapes: Shapes where not all sides and angles are equal. In an irregular shape, the sides can have different lengths, and the angles can vary in size.
The below figure shows the difference between regular and irregular 2D shapes.
Difference between 2D and 3D Shapes
2D Shapes: These are flat shapes that only have two dimensions: length and width. You can draw them on a piece of paper or see them on a screen. They don’t have any thickness or depth. Examples of 2D shapes include squares, circles, and triangles. Think of a drawing of a square – it’s flat and stays on the paper.
3D Shapes: These are solid shapes that have three dimensions: length, width, and height (or depth). Unlike 2D shapes, 3D shapes take up space around them. You can hold a 3D shape in your hand, like a ball or a box. Examples of 3D shapes include cubes, spheres, and cylinders. A 3D shape has thickness, so it doesn’t just lie flat.
The big difference is that 2D shapes are flat, while 3D shapes are solid and can be held!
The below table shows a comparison between 2D and 3D shapes.
Common 2D Shapes
Some of the most common 2D shapes are:
- Circle: A round shape where every point is the same distance from the center. Examples: wheels, coins and bangles.
- Square: A shape with four equal sides and four right angles. Examples: chessboards and tiles.
- Rectangle: Similar to a square but with two longer sides. Examples: doors and books.
- Triangle: A shape with three sides. Examples: road signs and pyramids.
- Hexagon: A six-sided shape, like a honeycomb.
- Pentagon: A shape with five sides, often seen in patterns and certain structures.
- Octagon: A shape with eight sides. The most common example is a stop sign.
Area and Perimeter of 2D Shapes
Area is the amount of space inside a shape. It tells us how much surface the shape covers. Imagine filling a square with little blocks. If the square is 3 units on each side, the area is 3 times 3, which equals 9 blocks. So, the area tells us how many blocks we can fit inside the shape. The area helps us understand how much space is inside the shape.
Perimeter is the distance around the outside of a shape. It’s like measuring the fence needed to go all the way around a yard. It measures the total length of all the sides. For the same square with sides of 3 units, you would add the lengths of all four sides together (3 + 3 + 3 + 3 = 12 units). The perimeter tells us how far we would have to walk to go all the way around the shape.
2D Shapes Around Us
We see 2D shapes all around us, in objects like books (rectangles), coins (circles), and traffic signs (triangles). We can easily draw 2D shapes with just a pencil and paper, making them fun to explore and create. 2D shapes can be combined to create new shapes, like making a house with a rectangle for the body and a triangle for the roof.
Practice Quiz on 2d-Shapes
FAQs on 2D Shapes
- A 2D shape has symmetry if it can be divided into two identical halves. If a shape can be folded along a line and the two halves match exactly, it is said to have line symmetry (or reflection symmetry).
- A circle is a 2D shape with no straight sides or vertices. Every point on the circle is equidistant from its centre. Unlike polygons, which have straight sides, a circle has a continuously curved edge.
- A trapezoid has only one pair of parallel sides, while a parallelogram has two pairs of parallel sides.
- Triangles are categorized by their sides and angles:
- Equilateral triangle: All sides and angles are equal.
- Isosceles triangle: Two sides are equal, and two angles are equal.
- Scalene triangle: All sides and angles are different.
- Right triangle: One angle is 90°.
- Acute triangle: All angles are less than 90°.
- Obtuse triangle: One angle is greater than 90°.
- Polygons with more than four sides include:
- Pentagon: 5 sides
- Hexagon: 6 sides
- Heptagon: 7 sides
- Octagon: 8 sides
- Nonagon: 9 sides
- Decagon: 10 sides