NCERT Solutions for Class 9 Maths Exercise 11.1 Surface Areas and Volumes in Hindi and English Medium for session 2024-25. Class 9 Maths ex. 11.1 is revised as per the revised syllabus based on the latest NCERT books issued for CBSE 2024-25.

Class: 9 | Mathematics |

Chapter: 11 | Exercise: 11.1 |

Topic: | Surface Areas and Volumes |

Content Type: | Text, Videos and PDF format |

Session: | CBSE 2024-25 |

Medium: | Hindi and English Medium |

### Class 9 Maths Exercise 11.1 Questions in Detail

- Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.
- Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.
- Curved surface area of a cone is 308 cm² and its slant height is 14 cm. Find (i) radius of the base and (ii) total surface area of the cone.
- A conical tent is 10 m high and the radius of its base is 24 m. Find (i) slant height of the tent. (ii) Cost of the canvas required to make the tent, if the cost of 1 m² canvas is ₹70.
- What length of tarpaulin 3 m wide will be required to make conical tent of height 8 m and base radius 6 m? Assume that the extra length of material that will be required for stitching margins and wastage in cutting is approximately 20 cm (Use π = 3.14).
- The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white-washing its curved surface at the rate of ₹210 per 100 m².
- A joker’s cap is in the form of a right circular cone of base radius 7 cm and height 24 cm. Find the area of the sheet required to make 10 such caps.
- A bus stop is barricaded from the remaining part of the road, by using 50 hollow cones made of recycled cardboard. Each cone has a base diameter of 40 cm and height 1 m. If the outer side of each of the cones is to be painted and the cost of painting is ₹12 per m², what will be the cost of painting all these cones?

### NCERT Solutions for Class 9 Maths Exercise 11.1

Class 9 Maths Exercise 11.1 is related to surface area of cone or conical figures. Solutions are given here in PDF and Videos format to download and use offline. Solutions are simplified using step by step explanation so that student can understand it easily.

### Class 9 Maths Exercise 11.1 Explanation

The purpose of the Tiwari Academy’s NCERT (ncert.nic.in) solutions for Maths class 9 is to help the students. It extends their knowledge of the area, perimeter, and volume also include surface area and lateral surface area.

While doing the practice of the chapter you must know a few most important definitions that shall induce the knowledge of the few points that you missed in the concept. The useful definitions are given here to help the students during the solution of the NCERT Questions.

#### Definitions and Terms related to Exercise 11.1

Axis – A line of reference about which a point, object, a line is drawn or measured. In a symmetrical shape. The Axis is usually a line of symmetry. Apothem is the line that connects the center of a regular polygon with one of its sides. The line is perpendicular to the side.

Radius – this is the definition that you must have studied in the previous classes and might have used to measure many times in questions. But formally, it is the distance from the geometric center of the curved shape to its circumference. In 9th mathematics chapter 11 from NCERT solutions, you will study various other shapes mainly 3-dimensional figures such as a sphere, hemisphere, cylinder, and other similar figures.

##### Shapes and concepts are intertwined

For the triangular related shapes, you will study the pyramid, right circular cone. The similarities between the two figures are that they both are 3-dimensional triangular figures. However, they also contain properties of a square, circle, and triangle at the base.

That is why it is absolutely vital for the students to read the question carefully to note it down. Then construct the rough figure before calculating its area, volume, lateral surface. Here, we will calculate the areas that doesn’t have any fix formulae. You will be given some of the important properties through which you will be able to calculate the solutions.

###### Way to calculate Surface Areas in Exercise 11.1

Finding surface area of figures are one of the trickiest parts of the chapter 11. If you see the figures given here illustrates how a triangular right angle cone contains qualities of the circle, triangle, and cylinder. If it is hollow inside, it could be round at the bottom, or the base could be square.

There are some of the direct formulae that you must remember to make calculation faster. In exercise 11.1 there are 8 questions. Most of them require to calculate the surface area in one way or the other.

### What is the concept behind exercise 11.1 of class 9 Maths?

Students can learn the basics of mensuration through Exercise 11.1 chapter 11 from class 9 Maths NCERT textbook. They can learn here about curved surface area of a cone. Questions in ex 11.1 is confined to CSA of cone in multiple application. Students can also learn the formulae to calculate the total surface area, perimeter of base of cone, and volume of different shapes.

### Which is the best question in class 9 mathematics exercise 11.1 for exams?

There are total 8 questions in ex 11.1 of 9th Mathematics. Out of these, question 5 and 8 are considered as the best expected questions for the exams. Question number 5 is tricky to solve but in 8th question we have to put formula only. Apart from this, students can also learn to understand the relationship between the different measurements of a shape.

### How to prepare for exercise 11.1 of class 9 NCERT Maths?

There are many ways to improve the work in exercise 11.1 of chapter 11 of class 9 NCERT Mathematics. First of all memorise the formulae and use them to reinforce the knowledge by writing the answers. Make sure to understand the concepts of slant height of cone thoroughly before attempting any questions. Regularly revise the topics to ensure that you remember them better.