What are 2D Shapes? Give some Examples.
Definition: 2D shapes in geometry can be defined as a shape or figure with two dimensions, length, and width. Two-dimensional or 2D shapes are generally measured in two faces as they don’t have a thickness, the third dimension, as in the case of a prism or a cube. Examples of 2D shapes are circles, triangles, rectangles, squares, and the pentagon.
What does 2D mean?
2D stands for two-dimensional. Dimensions are the measurements of the figures. They can be measured in terms of length, width, depth, and height.
What is a Circle?
A circle is a two dimensional or 2D shape, made from a single curved line. It has no straight sides. Here are some examples of the shape of a circle that we observe in day to day life.
What are Triangles?
Triangles are two-dimensional or 2D shapes with three sides and three vertices.
The sides or edges are the three lines that create the triangle, whereas the vertices are the tip of the points where two sides meet.
What are Rectangles?
A rectangle is a two dimensional or 2D shape with two short sides and two long sides. There are four sides and four vertices in a rectangle. Here are some examples of rectangles that we see everyday.
What are Squares?
A square is a two-dimensional or 2D shape with four equal sides and four vertices.
Did you know that all squares are rectangles but not all rectangles are squares?
This is because rectangles only have equal opposite sides, but all squares have equal sides, always! That is, even their opposite sides are equal, hence a square is a rectangle. Now, a rectangle is not a square as all the sides of a rectangle are not equal but all sides of a square are.
Name some other 2D Shapes
Along with squares, circles, rectangles, and triangles, there are other 2D shapes that you would have come across.
- Quadrilaterals – These are four-sided two-dimensional or 2D shapes. They have four sides and four vertices. A square, a kite, a rectangle, a rhombus, a trapezium, and a parallelogram, are quadrilaterals.
- Pentagons – These are five-sided two-dimensional or 2D shapes with five sides and five vertices.
- Hexagons – These are six-sided 2D shapes with six sides and six vertices.
- Octagons – These are eight-sided two-dimensional or 2D shapes with eight sides and eight vertices.
Similarly, heptagons are seven-sided figures that have seven vertices, nonagons have nine sides and vertices and decagons come with ten sides and vertices. We call these shapes “polygons”.
Why is it that these shapes are called polygons? Polygons are closed shapes with straight sides and 2D figures are a great example of polygons. Have a look at the following shapes.
Solved Two Dimensional Shapes Examples
Example 1: What do we say when two straight lines of a shape meet?
Solution: when two straight lines of a 2D shape meet, we call it a vertex.
Example 2: How many sides does the following figure have?
Solution: This is a 2D shape as we can see. Let us now count the number of sides of this figure. Number of sides of the shape = 5
It’s a pentagon as it has five sides.
Example 3: Count the sides and vertices of this shape.
Solution: This is a 2D shape, and let us count the sides.
Number of sides of this shape = 6
As we know, the number of sides is equal to the number of vertices in 2D shapes. Thus, the number of vertices = 6
This is a hexagon with 6 sides and 6 vertices.
Example 4: How many vertices does this shape have?
Solution: Let us first count the sides and the number of vertices of the shape.
Number of sides = 4
The number of vertices is the same as the number of sides for 2D shapes, hence the number of vertices is 4.
There are 4 vertices for this shape.
Example 5: Samuel draws two squares and two hexagons. How many sides and vertices did he draw altogether?
Solution: According to the question,
These are the shapes of squares and hexagons. Now, let us count the sides and vertices of both shapes.
Number of sides of the two squares = 8
Number of vertices of the two squares = 8
Similarly, the number of sides of the two hexagons = 12
Number of vertices of the two hexagons = 12
So, the total number of sides and vertices that Samuel drew was, 8 + 8 + 12 + 12 = 40
Samuel drew 40 sides and vertices altogether.
Example 6: Can you find the sides and vertices of the following shape:
Solution: Let us first count the sides and the number of vertices of the shape.
Number of sides = 6
The number of vertices is the same as the number of sides for 2D shapes, hence the number of vertices is 6.
There are 4 vertices for this shape.
We can call this shape a hexagon because of its 6 sides.
Example 7: The following image has been created by joining 2D shapes. Label the shapes with their appropriate names.
Solution: Carefully look at the shapes that have created this train engine. Starting from the left-hand side, the engine of the train starts off with a red-colored three-sided shape, a triangle. Then comes the body of the engine. The yellow-colored shape is a four-sided shape and it’s a rectangle. This is because two of its sides are different from the other two sides.
The wheels of the engine have a circular shape and hence, they are circles. The thin blue wheel holder above the circles has four sides and it’s a rectangle because of its shape. The whistleblower above the body of the train has 3 2D shapes. The red part is a rectangle as it has four sides, the blue figure above it is a rectangle as well, and the yellow shape above the blue rectangle has four sides. We can call it a quadrilateral.
Now, moving to the coach where the driver sits. The large blue figure is a rectangle again, as you can see from its sides. The window in the coach is a yellow square because of its equal sides.
The figures that form the train are hence labeled.
If you look around you, there will be many 2D shapes of various forms that you have barely noticed before. For example, a soccer ball that is circular in shape, your lunchbox that could be rectangular, the rectangular shaped books that you study, the circular frisbee that you play with friends, and the wall clock, which may be circular in shape.
Even though both these shapes are polygons, the difference between them is that an octagon has eight sides and eight vertices while a pentagon has five sides and five vertices.
A circle is a 2D shape that is just one curved line. So it does not have any straight lines that act as sides to intersect and form a vertex or multiple vertices as seen in a polygon. Hence, a circle cannot have sides and vertices.