Study Better With RS Aggarwal Solutions for Class 8 Maths Chapter 20

Now the NCERT Solutions for Class 8 Maths Chapter 20 are readily available in PDF format at the official website of Vedantu. These RS Aggarwal Class 8 Solutions Chapter 20 PDF can also be downloaded and stored on your devices. Once you download them, you can refer to them for quick revision of important formulas anytime anywhere, even when there is no internet connectivity.

Students can cover this chapter in a unique do-learn-do sequence using math formulas PDF.  Students can use these Math formulas to:

• Score higher on both class and board exams.

• On-time completion of the curriculum

• Thorough revision

• Formulas are simple to remember. They keep track of their time for the final exams.

• Understand the mathematical formula strengths and shortcomings.

• Take Vedantu online tuitions to clear up any worries while tackling any problem.

Volume and Surface Areas of Solids in Maths for Class 8

We come across several solids of diverse shapes and sizes in our daily lives, for which we may calculate both surface area and volume. We must calculate the surface area and volume of the things in our environment. But what if these basic shapes combine to generate a new shape that isn't the same as the original? The question now is how you'll figure out how to determine the volume, surface area, and area of new objects. We must observe the new form while calculating the surface area and volumes of these new shapes. Below is a detailed discussion that will help you understand these items and their calculations better.

We see many 3-D objects which are solid in our day-to-day lives like a book, pencil box, football, cylinder, etc. These objects occupy some space and possess 3 dimensions which are length, breadth, and height. Some of these shapes have identical or congruent faces like a cylinder that has two circular bases. The formulas and methods of measuring the volume and surface areas of such shapes are discussed below:

• The Surface Area of a Solid - This is given by the sum of areas of all of the solid's faces or outer parts.

• The Volume of a Solid - This is the capacity of a solid shape or the space inside the figure.

• The Curved Surface Area - CSA is found by measuring the areas of all the curved surfaces of a solid shape.

• The Lateral Surface Area - LSA is the area around the sides, excluding the top and the bottom faces.

• The LSA and CSA of a solid could be different, same, or overlap, depending on the shape of the solid.

• The Surface Area of a Cube - If the sides of a cube are equal to l then its surface area is 6l² since a cube has 6 square sides.

• Surface Area of a Cuboid - If the measurements of a cuboid are; height = h, length = l, and breadth = b then its surface area = 2 (b * h + h * l + l * b) = 2 (bh + hl + lb)

• The Surface Area of a Cylinder - For a cylinder with a height of h and radius of its circular base as r, its surface area is given by the formula 2 * π * r(r + h)

• The Volume of a Cuboid - For a cuboid with height = h, length = l, and breadth = b, the volume is given by l * b * h.

• The Volume of a Cube - Cube is a special type of cuboid where length, breadth, and heights are the same i.e. h = l = b hence its volume is l3

• The Volume of a Cylinder - If a cylinder has a height of h and its circular region has a radius of r then it's volume = π * r(r + h) = π r2h

• Lateral or Curved Surface Area of a Cube - The formula for this is 4l2 where l is the length of the cube.

• Lateral or Curved Surface Area of a Cuboid - The formula for this is 2h (l + b) where h is the height, l is the length, and b is the breadth of the cuboid.

• Lateral or Curved Surface Area of a Cylinder - The formula for this is 2πrh where r is the radius of its circular base and h is the height of the cylinder.

• Exercises

1. 20 A - There are 30 questions in this exercise which are a mix of short and long type answers. Some of the questions have subparts.

2. 20 B - It has 21 questions which are mostly short answer types.

3. 20 C - This exercise has 30 short type answers questions.

4. Test paper - This has 13 questions.

Two Methods for Measuring Solid Figures

• Taking measurements of the solid's surface (or border). It's known as the solid figure's surface area.

• Measuring the area encircled by the solid figure in space. The volume of a solid figure is what it's termed.

As a result, the surface area of a solid figure is measured, whereas the volume of the space region surrounded by the solid figure is measured. Volume is measured in cubic units, just like area is measured in square ones. The unit for volume is cm³(cube)  if the unit is chosen as a unit cube with a side of 1 cm, m³(cube) if the unit is chosen as a unit cube with a side of 1m, and so on.

There are many circumstances in daily life where we must find the surface area, as well as many situations where we must determine the volume. If we want to whitewash the walls and ceiling of a room, for example, we must first determine the surface areas of the walls and ceiling. If, on the other hand, we want to store milk or water in a container or food grains in a godown, we'll need to calculate the volume.

All the Exercise questions with solutions in Chapter-20 Volume and Surface Area of Solids are given below:

Exercise  (Ex 20A) 20.1

Exercise  (Ex 20B) 20.2

Exercise  (Ex 20C) 20.3

Preparation Tips for RS Aggarwal Class 8 Maths Chapter 20

• Volumes and surface area problems are dependent a lot on how well you remember the formulas and apply them. Hence keep a copy of all formulas in a tabular form handy with you while practising Class 8 Maths RS Aggarwal Chapter 20 Solution.

• Practising Maths as much as you can is key to getting a good grasp on any topic hence you must go through all the problems in RS Aggarwal Class 8 Chapter 20 Solutions by Vedantu and focus on the ones which seem difficult to you.

• Do not avoid topics with less weightage since building a good foundation in class 8 is required to get good scores in higher classes.

After Referring to these Solutions, You’ll be Able to:

• Define the terms surface area and volume of a solid figure; 
• Identify situations in which surface area and volume of a solid figure are needed;
• Find the surface areas of cuboids, cubes, cylinders, cones, spheres, and hemispheres using their respective formulae; and
• Find the volumes of cuboids, cubes, cylinders, cones, spheres, and hemispheres.

Get this solution file to clarify your doubts related to this chapter. Boost your confidence by learning how the experts solved the exercise problems. Practice using these techniques and understand how to save time while solving questions in an exam. Download this file today and make your study material of volume and surface area of solids complete.