NCERT Solutions for Class 9 Maths Chapter 13
Download here the NCERT Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes Exercise 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8 and 13.9 in English Medium as well as Hindi Medium updated for session 2021-2022 CBSE Second Term Examination. UP Board Students of Class 9 (High School) are using NCERT Book in session 2021-2022, so they can also using these textbooks solutions as UP Board Solutions for Class 9 Maths Chapter 13. Here, they can download Prashnavali 13.1, Prashnavali 13.2, Prashnavali 13.3, Prashnavali 13.4, Prashnavali 13.5, Prashnavali 13.6, Prashnavali 13.7, Prashnavali 13.88 and Prashnavali 13.9 in Hindi Medium to use offline for session 2021-22. NCERT Solutions for class 9 chapter 13 is applicable for CBSE Delhi Board, MP Board, UP Board – High School, UK Board, Gujrat Board and other board using NCERT Books 2021-22. NCERT Solutions 2021-2022 for other are also given in downloadable format.
NCERT Solutions for Class 9 Maths Chapter 13
Class 9th Maths Exercise 13.1 Solutions
Class 9th Maths Exercise 13.2 Solutions
Class 9th Maths Exercise 13.3 Solutions
Class 9th Maths Exercise 13.4 Solutions
Class 9th Maths Exercise 13.5 Solutions
Class 9th Maths Exercise 13.6 Solutions
Class 9th Maths Exercise 13.7 Solutions
Class 9th Maths Exercise 13.8 Solutions
Class 9th Maths Exercise 13.9 Solutions
|Class: 9||Maths (English and Hindi Medium)|
|Chapter 13:||Surface Areas and Volumes|
9th Maths Chapter 13 Solutions in English & Hindi Medium
Download free NCERT Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes all exercises which are given below in PDF format to download for new academic session 2021-22. NCERT Solutions as well as NCERT Solutions Offline Apps are updated for new academic session 2021-2022 based on latest CBSE Syllabus 2021-22. NCERT Books are now implemented in Uttar Pradesh also. So, students can download UP Board solutions for class 9 Maths chapter 13 all exercises from here.
Class 9 Maths Exercise 13.1 and 13.2 Solutions in Video
Class 9 Maths Exercise 13.3 and 13.4 Solutions in Video
Class 9 Maths Exercise 13.5 and 13.6 Solutions in Video
Class 9 Maths Exercise 13.7 and 13.8 Solutions in Video
Class 9 Maths Exercise 13.9 Solutions in Video
Class 9 Maths Chapter 13 Practice Questions with Solution
What are the formulae for Cuboid?
Cuboid: A cuboid is a solid bounded by six rectangular plane surfaces for example match box, brick, books, etc. are cuboid.
1. Surface area (or total surface area) of cuboid = 2 (lb + bh + hl) square units
2. Lateral surface area of cuboid = 2(l + b)h square units
3. Diagonal of a cuboid = √[l² + b² + h²] units
4. Total length of a edges of a cuboid = 4 (l + b + h) units
5. Volume of cuboid = lbh cubic units
What are the formulae for Cube?
Cube: A cuboid whose length, breadth and height are equal, is called a cube.
1. Surface area (or total surface area) of cuboid = 6a² square units
2. Lateral surface area of cuboid = 4a² square units
3. Diagonal of a cuboid = √3a units
4. Total length of a edges of a cuboid = 12a units
5. Volume of cuboid = a³ cubic units
What is meant by a Cylinder? Write its formulae?
Cylinder: A solid generated by the revolution of a rectangle about one of its sides which is kept fixed is called right circular cylinder.
Curved Surface Area (CSA) = 2πrh square units
Total Surface Area (TSA) = 2πr(r + h) square units
Volume = πr²h cubic units
What do you understand by a Cone? Write its Formulae?
Cone: A right circular cone is solid generated by revolving a line segment which passes through a fixed point and which makes a constant angle with a fixed line.
Slant Height = √[r² + h²]
Curved Surface Area (CSA) = πrl square units
Total Surface Area (TSA) = πr(r + l) square units
Volume = 1/3 πr²h cubic units
What are the basic formulae of Sphare?
Sphere: A sphere is three dimensional figure which is made up of all points in the space, which lie at a constant distance, form a fixed point called the centre of the sphere and the constant distant is called its radius.
Curved Surface Area (CSA) = Total Surface Area (TSA) = 4πr² square units
Volume = 4/3 πr³ cubic units
Important Notes on 9th Maths Chapter 13
Surface area of a solid body is the area of all of its surface together and it is always measured in square units. Surface area is also known as total surface area (TSA).
Space occupied by an object (solid body) is called the volume of the object. Volume is always measured in cubic units.
Important Questions on 9th Maths Chapter 13
The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 cm³ of wood has a mass of 0.6 g.
Inner radius of cylindrical pipe r = 24/2 = 12 cm,
outer radius R = 28/2 = 14 cm and
length h = 35 m
Volume of cylindrical wooden pipe
= 22/7 × (14²-12²)×35
= 22 × (196 – 144) × 5
= 22 × 52 × 5
= 5720 cm³
Mass of cylindrical wooden pipe
= 5720 × 0.6 g
= 3432 g
= 3.432 kg [∵1 cm³ of wood has a mass of 0.6 g]
Hence, the volume of cylindrical wooden pipe is 3.432 kg.
A soft drink is available in two packs – (i) a tin can with a rectangular base of length 5 cm and width 4 cm, having a height of 15 cm and (ii) a plastic cylinder with circular base of diameter 7 cm and height 10 cm. Which container has greater capacity and by how much?
Length of tin can l = 5 cm, breadth b = 4 cm and height h = 15 cm
Volume of tin can = lbh = 5 × 4 × 15 = 300 cm³
Radius of plastic cylinder r = 7/2 = 3.5 cm and height H = 10 cm
Volume of plastic cylinder
= πr²H = 22/7 × 3.5 × 3.5 × 10
= 22 × 0.5 × 3.5 × 10
= 385 cm³
Difference between capacities of two packs = 385 – 300 = 85 cm³
Hence, the capacity of plastic cylindrical pack is greater than tin can by 85 cm³.
If the lateral surface of a cylinder is 94.2 cm² and its height is 5 cm, then find radius of its base.
Lateral surface area of cylinder C = 94.2 cm² and height h = 5 cm.
Let, the radius of cylinder = r cm
Lateral surface area of cylinder C = 2πrh
⇒ 94.2 = 2 × 3.14 × r × 5
⇒ r = 94.2/(3.14×10) = 3 cm
Hence, the radius of base is 3 cm.
It costs ₹ 2200 to paint the inner curved surface of a cylindrical vessel 10 m deep. If the cost of painting is at the rate of ₹ 20 per m², find inner curved surface area of the vessel.
Cost of painting the inner curved surface of cylindrical vessel = ₹ 2200 and
height h = 10 m.
Let, the inner radius of cylindrical vessel = r m
The inner curved surface area of cylindrical vessel = 2πrh
The cost of painting is at the rate of ₹ 20 per m² = ₹ 20 × 2πrh
According to question,
₹ 20 × 2πrh = ₹ 2200
⇒ 2πrh = 2200/20 = 110
Hence, the inner curved surface area is 110 m².
A patient in a hospital is given soup daily in a cylindrical bowl of diameter 7 cm. If the bowl is filled with soup to a height of 4 cm, how much soup the hospital has to prepare daily to serve 250 patients?
Radius of cylindrical bowl r = 7/2 = 3.5 and
height of soup inside the cylindrical bowl h = 4 cm
Volume of cylindrical bowl
= πr²h = 22/7 × (3.5)² × 4
= 22/7× 3.5 × 3.5 × 4
= 22 × 0.5 × 3.5 × 4 = 154 cm³
Therefore, the volume of soup per day for 250 patient
= 250 × 154
= 38500 cm³
Hence, hospital has to prepare 38500 cm³ soup daily to serve 250 patients.
The curved surface area of a right circular cylinder of height 14 cm is 88 cm². Find the diameter of the base of the cylinder.
Curved surface area of cylinder 88 cm² and height h = 14 cm
Let, the radius of base of cylinder = r cm
Curved surface area of cylinder = 2πrh
⇒ 88 = 2 × 22/7 × r × 14
⇒ 88 = 88r
⇒ r = 1 cm
Hence, the diameter of base of cylinder
= 2r = 2 × 1 = 2 cm
The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions to move once over to level a playground. Find the area of the playground in m².
Radius of roller r = 84/2 = 42 cm = 0.42 m and
length h = 120 cm = 1.2 m
Outer curved surface area of roller
= 2πrh = 2 × 22/7 × 0.42 × 1.2 = 2 × 22 × 0.06 × 1.2 = 3.168 m²
Area of ground levelled in on revolution = 3.168 m²
Therefore, area of ground levelled in 500 revolutions
= 500 × 3.168 = 1584 m²
Hence, the area of playground is 1584 m².
Curved surface area of a right circular cylinder is 4.4 m². If the radius of the base of the cylinder is 0.7 m, find its height.
Curved surface area of cylinder 4.4 m² and radius r = 0.7 m
Let, the height of cylinder = h m
Curved surface area of cylinder = 2πrh
⇒ 4.4 = 2 × 22/7 × 0.7 × h
⇒ 4.4 = 4.4h
⇒ h = 1 m
Hence, the height of the cylinder is 1 m.
Find the total surface area of a hemisphere of radius 10 cm. (Use π = 3.14)
Radius of hemisphere r = 10 cm
Surface area of hemisphere = 3πr²
= 3 × 3.14 × 10 × 10
= 942 cm²
Hence, the total surface area of hemisphere is 942 cm².