Last updated at March 3, 2017 by Teachoo

Transcript

Ex 13.3, 5 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). Tarpaulin will be on the curved surface area of tent Lets find curved surface area first Curved surface area of tent = πr l r = 6m, h = 8m Let slant height be = l We know that l2 = h2 + r2 l2 = "(8)2 + (6)2" l2 = "64 + " 36 l2 = 100 l = √100 l = √("102" ) l = 10 m Curved surface area of tent = πr l = (3.14×6×10) m2 = 188.4 m2 Now, Area of tarpaulin material = Area of tent (Length) × Breadth = Area of tent (Length) × 3 = Area of tent Length = 1/3 (Area of tent) = 188.4/3 = 62.8 m Length = 62.8 m Now, given that margin is 20 cm Total length = Length calculated + Margin = 62.8 m + 20 cm = 62.8 m + 20 × 1/100 m = 62.8 m + 0.2 m = 63 m

Chapter 13 Class 9 Surface Areas and Volumes

Example 2
Important

Ex 13.1, 6 Important

Ex 13.1, 7 Important

Ex 13.2, 3 Important

Ex 13.2, 4 Important

Ex 13.2, 9 Important

Example 6 Important

Ex 13.3, 3 Important

Ex 13.3, 5 Important You are here

Ex 13.4, 3 Important

Ex 13.4, 8 Important

Ex 13.4, 9 Important

Ex 13.5, 6 Important

Ex 13.5, 8 Important

Ex 13.5, 9 Important

Example 14 Important

Ex 13.6, 3 Important

Ex 13.6, 7 Important

Ex 13.7, 5 Important

Ex 13.7, 6 Important

Ex 13.7, 7 Important

Ex 13.7, 8 Important

Example 18 Important

Ex 13.8, 4 Important

Surface Area and Volume Formulas Important

Class 9

Important Questions for Exam - Class 9

- Chapter 1 Class 9 Number Systems
- Chapter 2 Class 9 Polynomials
- Chapter 3 Class 9 Coordinate Geometry
- Chapter 4 Class 9 Linear Equations in Two Variables
- Chapter 5 Class 9 Introduction to Euclid's Geometry
- Chapter 6 Class 9 Lines and Angles
- Chapter 7 Class 9 Triangles
- Chapter 8 Class 9 Quadrilaterals
- Chapter 9 Class 9 Areas of parallelograms and Triangles
- Chapter 10 Class 9 Circles
- Chapter 11 Class 9 Constructions
- Chapter 12 Class 9 Herons Formula
- Chapter 13 Class 9 Surface Areas and Volumes
- Chapter 14 Class 9 Statistics
- Chapter 15 Class 9 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.