Shapes and Designs Class 3 Notes CBSE Maths Chapter 5 [Free PDF Download]

Shapes

• Shapes provide an object's boundary.

• A boundary is created by mixing the curves, points, and line segments to form shapes. 

• Examples of shapes: circle, square, rectangle, triangle, and so on.

Different shapes

Different Types of Shapes

The following classification is used to determine the base of each shape:

• Open Shapes: Open shapes are made up of line segments or curves that do not intersect and are not continuous. 

Example: An open shape is represented by the letter C.

Open shape

• Closed Shapes: Closed shapes are those that can be traced without breaking. They both begin and end in the same location. 

Example: A closed shape is represented by the letter D.

Closed Shape

Solved Example 1: Is alphabet (A) a closed shape?

Ans: No, alphabet (A) is not a closed shape.

Solved Example 2: Give 3 examples of closed shape alphabets?

Ans: 3 examples of closed shape alphabets are (O), (B), and (D).

Solved Example 3: Give 2 examples of open shape alphabets?

Ans: 2 examples of open shape alphabets are (U), and (S).

Circle

• A circle is defined as a closed-form. 

• It's classified as a two-dimensional geometric shape with a round shape. 

• There are no lines or corners on it.

• For example, a vehicle's steering wheel, a pizza base, or a dartboard.

Circle

Oval 

• An oval is a slightly extended form that resembles a circle. 

• There are no straight lines or corners on it. 

• The number zero, for example (0).

Oval

Square

• It is a closed two-dimensional shape with four sides. 

• Each side is measured at the same length. 

• A chessboard and a carrom board, for example.

Square

Triangle

• A triangle is a three-sided geometric shape that is classified as two-dimensional. 

• For example, one slice of cheese burst pizza in the shape of sour nachos.

Triangle

Rectangle

• It is a shape with four sides. 

• It's a two-dimensional geometric shape with opposite sides that are the same length. 

• For example, a laptop screen, a touch screen phone, and so on.

Rectangle

Counting of Triangles

• For counting triangles, add numbers to the base of smaller triangles. Then add the base numbers to calculate the total number of triangles.

Solved Example 1: Annie wants to count the number of triangles present in the given image?

Counting Rectangles

Ans: Here, Annie wants to count the total number of triangles present in the image. So, Annie will use the concept of counting shapes to find how many triangles are present:

• Step1: Identify the different shapes present in the image. Here, in the above image, only triangles are present.

• Step2: Add the numbers to the base of the small triangles.

Base Triangles

• Step3: To calculate the total number of triangles, add base numbers.

Total Triangles

• Total number of triangles = 3

• So, the total number of triangles present in the image is 3.

Solved Example 2: Count the number of triangles present in the given image?

Counting Triangles

Ans: Here, we want to count the total number of triangles present in the image. So, we will use the concept of counting shapes to find how many triangles are present:

• Step1: Identify the different shapes present in the image. Here, in the above image, only triangles are present.

• Step2: Add the numbers to the base of the small triangles.

Base Triangle

• Step3: To calculate the total number of triangles, add base numbers.

Addition of base numbers of triangles

• Total number of triangles = 10

• So, the total number of triangles present in the image is 10.

Solved Example 3: Sam wants to count the number of triangles present in the given image?

Counting Triangle

Ans: Here, Sam wants to count the total number of triangles present in the image. So, Sam will use the concept of counting shapes to find how many triangles are present:

• Step1: Identify the different shapes present in the image. Here, in the above image, only triangles are present.

• Step2: Add the numbers to the base of the small triangles. Here, we have 2 small triangles in the first layer and 2 small triangles in the second layer.

Base Triangle

• Step3: To calculate the total number of triangles, add base numbers present on each layer.

Addition of base triangle

• Number of triangles in the first layer  = 3

• Number of triangles in the second layer = 3

• Total number of triangles in both layers = 3+3 = 6

• So, the total number of triangles present in the image is 6.

Edges of Shapes

• They are the lines that outline a shape.

• For example, a square has 4 edges.

Edges of a square

Corners of Shapes

• They are the pointed parts or vertices where edges meet.

• For example, a rectangle has 4 corners.

Corners of a rectangle

Solved Example 1: How many edges does a triangle have?

Ans: A triangle has 3 edges.

Solved Example 2: How many edges does a ball have?

Ans: A ball has zero edges.

Solved Example 3: How many corners does a square have?

Ans: A square has 4 corners.

Solved Example 4: How many corners does an oval have?

Ans: An oval has 0 corners.

Patterns

• We may make a variety of patterns or designs with different basic shapes.

• Weaving patterns, tiling patterns, and floor patterns are all examples of designs.

Different patterns

Practice Questions

Q1. Write (A) for closed shape and (B) for open shape in the following image.

Open and closed shapes

Q2. Count the number of different basic shapes in the following image.

Different basic shapes

Answers

Ans 1.

Open and closed shapes

Ans 2.

• Number of squares: 4

• Number of rectangles: 5

• Number of triangles: 5

• Number of circles: 4

• Number of ovals: 4

Importance of Shape and Design Class 3 Chapter 5