Class 8 Maths Mensuration Introduction

Introduction:

Mensuration deals with length, area and volume of different kinds of shape- both 2D and 3D.  It is based on the use of algebraic equations and geometric calculations to provide measurement data regarding  the width, depth and volume of a given object or group of objects. While the measurement results obtained by the use of mensuration are estimates rather than actual physical measurements, the

 Class_8_Maths_Mensuartion_Shapes

                                                       

calculations are usually considered very accurate.

There are two types of geometric shapes: 2D and 3D

 2D shapes are: Square, Rectangle, Parallelogram, Rhombus, Triangle, Trapezoid, Circle

 

3D shapes: They have surface area and volume.

 

Cube, Cuboids, Cylinder, Cone, Sphere, Prism, Pyramid.

 

Problem: A square and a rectangular field with measurements as given in the figure have the same perimeter. Which field has a larger area?

                     Class_8_Maths_Mensuartion_Shapes_1                                 

Solution:

Given: The side of a square = 60 m

And the length of rectangular field = 80 m

According to question,

Perimeter of rectangular field = Perimeter of square field

=> 2(l + b) = 4 * side

=> 2(80 + b) = 4 * 60

=> 160 + 2b = 240

=> 2b = 240 – 160

=> 2b = 80

=> b = 80/2

=> b = 40

Now, Area of Square field = (side)2 = (60)2 = 60 * 60 = 3600 m2

And Area of Rectangular field = length * breadth = 80 * 40 = 3200 m2

Hence, area of square field is larger.

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