Understanding 2D Shapes

Geometry teaches both 2D and 3D shapes in great length so that you can understand the various kinds of objects you will see in everyday life. These forms have distinct features and patterns. The shapes can differ based on a variety of characteristics, including angle, sides, length, height, width, area, volume, etc. We have been taught these 2D and 3D shapes from our primary school days. In this post, let’s examine several kinds of two-dimensional shapes.Understanding 2D Shapes


Basics Shapes on 2D Shapes

  • Circle

Circles, triangles, squares, rectangles, pentagons, quadrilaterals, hexagons, octagons, and other basic shapes are examples of 2D shapes. Every shape, with the exception of the circle, is regarded as a polygon since it has sides. A regular polygon is one that has equal numbers of sides and angles. An ellipse is a non-polygon form, as is the circle. While polygons have a closed structure with sides, circles and ellipse are also curved shapes. Let’s now talk about each shape individually.


A circle is a closed a two-dimensional object in which every point in the plane has equal distance from a fixed point known as the “center.” A radius is the length of the circle measured from its center to its outermost line. Real-world examples of circles include wheels, pizza, orbits, etc.Circle


A triangle is a two-dimensional polygon with three vertices and three edges. A triangle’s three angles add up to a total of 180°. The best illustration of a triangle form is found in pyramids. Here is where you may also learn about triangle characteristics.Triangle


A square is a two-dimensional polygon with four equivalent-length sides and all angles equal to 90 degrees. It is regarded as a regular quadrilateral in two dimensions. The square’s diagonals likewise split in half at a 90-degree angle. A square-shaped object would be a wall or a table with equal sides.Square


A rectangle is a 2D shape with four equal sides that run parallel to one another. In a rectangle, every angle is equal to 90 degrees. Examples of rectangles with length and width include bricks, TVs, and cardboard.Rectangle


A pentagon is a regular or irregular 2D polygon with five sides. Each exterior angle and each interior angle of a regular pentagon are 72° and 108°, correspondingly. Five diagonals are present. A great example of the pentagon shape is the Pentagon structure, which houses the US Department of Defense.Pentagon


An eight-sided polygon with regular or irregular sides is called an octagon. It is a two-dimensional shape with eight angles. 1080° is the total of an octagon’s inner angles. You can see the octagonal-shaped stop sign board by the side of the road.Octagon

Properties of 2D shapes

Below are the Properties of 2D shapes

2 D ShapesProperties of 2 D Shapes
SquareFour equal sidesFour equal angles(90°)Four axes of symmetry
Rectangle2 sets of 2 equal sidesFour equal angles(90°)Two axes of symmetry
TriangleIt can have no, 2 or 3 equal sidesIt can have no, 2 or 3 equal anglesIt can have up to 2 axes of 


CircleConstant diameter and 


The total angle of a circle is equal to 360 degreesAlmost infinite axes of 

symmetry going through

the centre

pentagon5 sides (can be equal or unequal)5 angles (can be equal or unequal)It can have up to 5 axes 

of symmetry

hexagon6 sides (can be equal or unequal)6 angles (can be equal or unequal)It can have up to 6 axes of 


Octagon8 sides (can be equal or unequal)8 angles (can be equal or unequal)It can have up to 8 axes of 


Parallelogram2 sets of 2 equal sides2 sets of 2 equal anglesUsually no axes of symmetry
RhombusAll sides the same length2 sets of 2 equal angles2 lines of symmetry
TrapeziumAt least 2 parallel sidesCan have pairs of equal 


It can have a line of 



Different Between 2D shapes and 3D Shapes

We know that 2d shapes are flat figures and 3d shapes are solid figures. Below are the few comparisons of these two types of shapes.

2d Shapes3d Shapes
It is a shape surrounded by three or more straight lines in a plane and sometimes with a closed curve.If a shape is surrounded by a no. of surfaces or planes then it is a 3D shape.
These shapes have no depth or height.These are also called solid shapes and unlike 2D they have height or depth.
These shapes have only two dimensions, say length and breadth, whereas curved shapes such as circle and ellipse have radii.These are shapes containing three dimensions such as depth (or height), breadth and length.
Area, perimeter can be found for these shapes.We can calculate their volume, CSA, LSA or TSA.
Examples: Circle, Triangle, Quadrilaterals, Polygons, etc.Examples: Cube, Cuboid, Sphere, Cylinder, Cone, etc.


Question to Practice

Q.1: What is the area of a square that has a side length equal to 4 inches?

  • Solution: Given, length of side of square = 4 inches
  • Area of square = side2 = (4) = 16 in2

Q.2: Given a circle with a radius of 7 cm, what is its area? π = 22/7)

  • Solution: Circle’s radius is 7 cm.
  • πr2 = (22/7) x 72 = 22 x 7 = 154 is the area of a circle.

Q.3: Find the perimeter of the rectangle whose length and breadth are 10 cm and 5 cm, respectively. Also, find its area.

Solution: Given,

  • Length of rectangle = 10 cm
  • Breadth of rectangle = 5 cm
  • Area of rectangle = Length x Breadth = 10 x 5 = 50 cm2
  • Perimeter of rectangle = 2(Length + Breadth) = 2(10+5) =  2 x 15 = 30 cms

Area and Perimeter In 2D Shapes

The area is the region covered by a 2d shape on a plane. The areas for different shapes are given below:

2d ShapeAreaPerimeter
CircleΠr2 (R is the radius of the circle)2πr
Triangle½ (Base x height)Sum of three sides
RectangleLength x Breadth2(Length + Breadth)
Rhombus½ (Product of diagonals)4(Side)
ParallelogramBase x Height2 (Base + Side)



In conclusion, 2D shapes are fundamental geometric objects that exist in two dimensions, having only length and width. They come in a variety of forms, including basic shapes like circles, triangles, squares, and rectangles, as well as more complex polygons. Understanding 2D shapes involves recognizing their properties, such as perimeter and area, and classifying them as regular or irregular, convex or concave. These shapes play a vital role in mathematics, art, architecture, and many real-world applications, serving as the building blocks for more advanced geometric concepts and problem-solving in various fields.

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