13. Surface Areas and Volumes Mathematics Exercise - 13.7 class 9 Maths in English - CBSE Study
NCERT Solutions for Class 9 Mathematics are carefully prepared according to the latest CBSE syllabus and NCERT textbooks to help students understand every concept clearly. These solutions cover all important 13. Surface Areas and Volumes with detailed explanations and step-by-step answers for better exam preparation. Each Exercise 13.7 is explained in simple language so that students can easily grasp the fundamentals and improve their academic performance. The study material is designed to support daily homework, revision practice, and final exam preparation for Class 9 students. With accurate answers, concept clarity, and structured content, these NCERT solutions help learners build confidence and score higher marks in their examinations. Whether you are revising a specific topic or preparing an entire chapter, this resource provides reliable and syllabus-based guidance for complete success in Mathematics.
Class 9 English Medium Mathematics All Chapters:
13. Surface Areas and Volumes
7. Exercise 13.7
EXERCISE 13.7
Assume π = 22/7, unless stated otherwise.
1. Find the volume of the right circular cone with
(i) radius 6 cm, height 7 cm (ii) radius 3.5 cm, height 12 cm
Solution:
2. Find the capacity in litres of a conical vessel with
(i) radius 7 cm, slant height 25 cm (ii) height 12 cm, slant height 13 cm
Solution:
(i) h2 = 252 - 72
3. The height of a cone is 15 cm. If its volume is 1570 cm3, find the radius of the base.(Use π = 3.14)
Solution:
Height = 15 cm, volume = 1570 cm3
4. If the volume of a right circular cone of height 9 cm is 48π cm3, find the diameter of its base.
Solution:
Height = 9 cm, volume = 48π cm3
5. A conical pit of top diameter 3.5 m is 12 m deep. What is its capacity in kilolitres?
Solution:
Diameter = 3.5 cm , height = 12 cm , radius = 1.75
6. The volume of a right circular cone is 9856 cm3. If the diameter of the base is 28 cm, find
(i) height of the cone (ii) slant height of the cone
(iii) curved surface area of the cone
Solution:
Volume = 9856 cm3 , diameter = 28 cm , radius = 14cm
7. A right triangle ABC with sides 5 cm, 12 cm and 13 cm is revolved about the side 12 cm. Find the volume of the solid so obtained.
Solution:
Height = 12 cm , radius = 5 cm
8. If the triangle ABC in the Question 7 above is revolved about the side 5 cm, then find the volume of the solid so obtained. Find also the ratio of the volumes of the two solids obtained in Questions 7 and 8.
Solution:
Height = 5 m , radius = 12 m
9. A heap of wheat is in the form of a cone whose diameter is 10.5 m and height is 3 m. Find its volume. The heap is to be covered by canvas to protect it from rain. Find the area of the canvas required.
Solution:
Diameter = 10.5 m, height = 3 m , radius = 5.25
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