Learn finding Area, Circumference and Perimeter

Hello Friends, in today's class we all are going to discuss about some of the most interesting topics of mathematics, geometry, area, circumference and perimeter which comprises of a huge part of cbse question bank. Here I am going to tell you the best way of understanding these terms.
Now start with basic geometry help:
Geometry is the basic about the point, lines, angle, area, volume etc. And to learn it we should have knowledge of some terms:

1.    Point:

Point is represented as a dot in a plane. Usually we denote it with a capital letter.

2.    Line:

Line is described as the collection of points. Line does not have any end point i.e. it extends forever.

3.    Line segment:

Line segment is a part of line that has two end points.

4.    Ray:

Ray is defined as the a line which starts from a point and extends in a direction forever in simple words we can say that line with a single end point.           

5.    Angle:

When two rays start from same point then they form an angle between them.                                  

                   

6.    Plane:

Plane can be defined as a flat surface that extends forever.                              

And now we will start learning about the terms area, circumference and perimeter. And remember one thing that all these terms have their own geometrical formulas for each and every figure i.e. formulas of area are different for circle, triangle, rectangle etc. and similarly this is also in the case of circumference and perimeter. Click here to know more about Geometry.                                  

Now one by one we will go through to each term and see their formulas for different shapes:

1.    Area:

Area is calculated in “square” units and the area of a given plane surface is equal to the number of squares required to cover it.

1.    Square: b²                                                   

2.    Rectangle: l x b => ( length x breath )

3.    Parallelogram: b x h => ( breath x height )

4.    Trapezoid: h ( b₁ + b₂ )

                  2

5.      Circle: pi r²   ( pi = 3.14)

6.      Ellipse: pi r₁² r₂²

7.    Triangle: ½ ( b x h )

8.    Equilateral triangle: sqrt ( 3 ) ( a² )

                                      4

         
             Let’s take an example:
            Q1. Find the area of a circle whose diameter is 4 cm. ( pi = 3.14 )
            Solution:
                        Diameter of a circle = 2r
                        Therefore     4 = 2r
                                             r = 2 cm
                        Area of a circle = pi r²
                                                                             = 3.14 x 2²
                                                 = 12.56 cm²

2.    Perimeter:

Perimeter is defined as the sum of all sides of a figure.

1.    Square: 4b 

2.    Rectangle:2p + 2q 

3.    Triangle:p + q + r   

4.    Circle: 2pi r  

5.    Circle:  pi d (where d is the diameter)

           Let’s take an example:
            Q1. Find the perimeter of a square whose edge length is 4 cm.
            Solution:
                        Perimeter of a square = 4 x (edge length)
                                                            = 4 x 4
                                                            = 16 cm

3.    Circumference:

Circumference is defined as the distance around any closed surface.

1.    Circle: 2 pi r

               Let’s take an example:
            Q1. Find the circumference of a circle whose radius is 4 cm. ( pi = 3.14 )
            Solution:
                        Circumference of a circle = 2 pi r
                                                                 = 2 x 3.14 x 4
                                                                 = 25.12 cm

This is all about the finding Area, Circumference and Perimeter and if still it is not clear to anyone they can refer to internet and text books for understanding it more precisely. You can also refer grade V blog for further reading on geometry. You can read more maths topics of different grades such as Numbers in Grade IV on Internet.