Surface Area and Volume Class 10 Notes
Home/CBSE/Surface Area and Volume Class 10 Notes

# Surface Area and Volume Class 10 Notes

In this post, you’ll learn about the important definitions, concepts, and formulas related to surface area and volume class 10 notes. Let’s get started!Surface area is a measure of the total area that the surface of an object occupies. It is typically measured in square units, such as square meters or square centimetres. The formula for the surface area of a 3-dimensional object depends on the shape of the object. For example, the surface area of a cube is 6 times the area of one of its faces, while the surface area of a sphere is 4 times the area of a great circle on the sphere.Volume is the measure of the amount of space occupied by an object. It is typically measured in cubic units, such as cubic meters or centimetres. The formula for volume also depends on the shape of the object. For example, the volume of a cube is the cube of the length of its one side, and the volume of a sphere is (4/3) times pi times the cube of its radius.

The topics covered in the surface area and volume unit typically include:

• The surface area and volume of basic 3-dimensional shapes such as cubes, spheres, cylinders, cones, and rectangular prisms
• The volume of basic 3-dimensional shapes such as cubes, spheres, cylinders, cones, and rectangular prisms
• Finding surface area and volume of composite figures, which are made up of basic 3-dimensional shapes
• Using the concepts of surface area and volume to solve real-world problems, such as finding the amount of paint needed to cover the surface of a room or the volume of a swimming pool
• Understanding the relationship between surface area and volume and how changes in one affect the other
• Using the formulas of surface area and volume to find the missing dimensions of an object, such as finding the radius of a sphere when given its surface area
• Understanding the concept of similar figures and how to use it to find the surface area and volume of similar figures
• Using the concept of ratio and proportion to find the surface area and volume of similar figures
• Applying the concept of surface area and volume to find the volume of irregular figures
• Solving word problems involving surface area and volume

## Surface Area of Basic 3-D Shapes

The section in the Surface Area And Volume Class 10 Notes typically covers the surface area of basic 3-dimensional shapes. These shapes include

• Cube: A cube is a three-dimensional shape with six square faces of equal size. The formula for finding the surface area of a cube is 6 * (side length)2.
• Sphere: A sphere is a three-dimensional shape with a curved surface. The formula for finding the surface area of a sphere is 4 * pi * (radius)2, (4πr2).
• Cylinder: A cylinder is a three-dimensional shape with two circular bases and a curved surface. The formula for finding the surface area of a cylinder is 2 * pi * (radius)*h + 2 * pi * (radius)2, (2πrh+2πr2).
• Cone: A cone is a three-dimensional shape with a circular base and a pointed top. The formula for finding the surface area of a cone is pi * (radius)2 pi * (radius) * (slant height), (𝛑rs+𝛑r²).
• Rectangular prism: A rectangular prism is a three-dimensional shape with six rectangular faces. The formula for finding the surface area of a rectangular prism is 2 * (length * width + height * length + height * width), 2(wl+hl+hw).

It’s important to note that these formulas are for the basic shapes, and it’s quite important to be able to identify the type of shape for which you need to find the surface area. It’s also important to understand the difference between surface area and volume.

## The Volume of Basic 3-D Shapes

The second section in the Surface Area And Volume Class 10 Notes typically cover the volume of basic 3-dimensional shapes. These shapes include

• Cube: A cube is a three-dimensional shape with six square faces of equal size. The formula for finding the volume of a cube is (side length)3.
• Sphere: A sphere is a three-dimensional shape with a curved surface. The formula for finding the volume of a sphere is (4/3) * pi * (radius)3.
• Cylinder: A cylinder is a three-dimensional shape with two circular bases and a curved surface. The formula for finding the volume of a cylinder is pi * (radius)2 * (height).
• Cone: A cone is a three-dimensional shape with a circular base and a pointed top. The formula for finding the volume of a cone is (1/3) * pi * (radius)2 * (height).
• Rectangular prism: A rectangular prism is a three-dimensional shape with six rectangular faces. The formula for finding the volume of a rectangular prism is length * width * height.

## Finding the Surface Area and Volume of Composite Figures

The third section in the Surface Area and Volume Class 10 Notes typically cover finding the surface area and volume of composite figures. A composite figure is made up of basic 3-dimensional shapes such as cubes, spheres, cylinders, cones, and rectangular prisms. To find the surface area and volume of a composite figure, you need to break it down into its basic components and add up each component’s surface area and volume.

For example, to find the surface area of a composite figure that is made up of a cube and a cylinder, you would first find the surface area of the cube using the formula 6 * (side length)2 and then find the surface area of the cylinder using the formula 2πrh+2πr2. Finally, you would add the surface areas of the cube and cylinder together to find the total surface area of the composite figure.

The same process can be applied to find the volume of a composite figure.

## Finding Surface Area and Volume to Solve Real-World Problems

The fourth section in the Surface Area and Volume Class 10 Notes typically covers using the concepts of surface area and volume to solve real-world problems. This includes using the formulas for surface area and volume to calculate how much paint is needed to cover a room, how much water is needed to fill a swimming pool, and so on.

For example, to calculate how much paint is needed to cover a room, you would first need to find the total surface area of the walls in the room. You would do this by measuring the length and height of each wall and multiplying them together to find the area of each wall. Then you would add the areas of all the walls together to find the total surface area of the walls. Once you have the total surface area, you can use this information to determine how much paint is needed to cover the walls.

To calculate how much water is needed to fill a swimming pool, you would first need to find the volume of the pool. You would do this by measuring the length, width, and depth of the pool and using the appropriate formula for the shape of the pool. Once you have the volume of the pool, you can use this information to determine how much water is needed to fill it.

It’s important to note that these examples are quite basic, and it’s also important to understand the unit of measurement for volume and surface area, for example, cm2 for volume and cm2 for surface area.

## The Relationship Between Surface Area And Volume

The fifth section in the Surface Area and Volume Class 10 Notes typically covers understanding the relationship between surface area and volume and how changes in one affect the other.

As the volume of an object increases, so does its surface area. This is because as the volume of an object increases, its size also increases, which means that its surface area will increase as well.

Conversely, as the surface area of an object decreases, so does its volume. This is because as the surface area of an object decreases, its size also decreases, which means that its volume will decrease as well.

For example, if you were to double the length, width, and height of a rectangular prism, its volume would increase by a factor of 8 (2 x 2 x 2), and its surface area would increase by a factor of 4 (2 x 2).

This relationship between surface area and volume is important to understand because it can be used to solve problems and predict how changes in one will affect the other.

## Formulas to Find the Missing Dimensions of an Object

The sixth section in the Surface Area and Volume Class 10 Notes typically covers using the formulas of surface area and volume to find the missing dimensions of an object. This can be done by using the formulas and solving for the unknown dimension.

For example, if you are given the surface area of a cube and asked to find the length of one of its sides, you can use the formula for the surface area of a cube, which is 6 * (side length)2. You can then rearrange the formula to solve for the side length.

Another example is if you are given the volume of a sphere and asked to find the radius, you can use the formula for the volume of a sphere, which is (4/3) * pi * (radius)3. You can then rearrange the formula to solve for the radius.

It’s important to have a good understanding of algebraic manipulation to be able to solve for the unknown dimension.

## The Concept of Similar Figures

The seventh point in the Surface Area and Volume of Class 10 Notes typically covers understanding the concept of similar figures and how to use it to find the surface area and volume of similar figures.

Similar figures are figures that have the same shape but different sizes. For example, a cube and a rectangular prism are similar figures if their corresponding faces are all in the same proportion.

When figures are similar, the ratio of corresponding side lengths, or the scale factor, is the same for all corresponding sides. Suppose two similar figures have corresponding side lengths that are in the ratio of 1:2. Then the ratio of the surface area and volume of the two figures will also be 1:2.

For example, if two similar figures have a scale factor of 2, then the surface area of the larger figure will be 4 times the surface area of the smaller figure. The volume of the larger figure will be 8 times the volume of the smaller figure.

This concept of similarity can be useful when trying to find the surface area or volume of a figure if the dimensions of a similar figure are known.

### Surface Area And Volume Formulas

Formulas for the surface area and volume of basic 3-dimensional shapes that are typically covered in class 10:

Surface area formulas:

• Cube: Surface area = 6 * (side length)2
• Sphere: Surface area = 4 * pi * (radius)2
• Cone: Surface area = pi*r2 + pi*L*r
• Rectangular prism: Surface area = 2 * (length * width + height * length + height * width)

Volume formulas:

• Cube: Volume = (side length)3
• Sphere: Volume = (4/3) * pi * (radius)3
• Cylinder: Volume = pi * (radius)2 * (height)
• Cone: Volume = (1/3) * pi * (radius)2 * (height)
• Rectangular prism: Volume = length * width * height

## Problems

The tenth point section in the Surface Area and Volume Class 10 Notes typically covers solving word problems involving surface area and volume. These problems often involve real-world scenarios, such as finding the amount of paint needed to cover a room, the volume of water in a swimming pool, or the dimensions of a box.

Students need to be able to apply their understanding of the formulas for surface area and volume, as well as their ability to read and interpret the information given in the problem. They should be able to identify the relevant information, such as the dimensions of an object or the amount of paint needed, and use that information to calculate the solution.