Class 9 | Chapter 13 | Surface areas and Volumes | Exercise 13.3 | Question 5

Question 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).

Cone

Cone is an interesting geometric figure to understand and work upon. You come across so many items in daily life that are conical in shape – like a picnic tent, an ice cream cone, a birthday cap and there are many more that you can think about.

In this chapter we will work on only right circular cones. To understand what a right circular cone is, watch the following video.

 

Lateral or curved surface area of cone = πrl

r = base radius, l = slant height

Total surface area of cylinder = πrl + πr² = πr (l + r)

r = base radius, l = slant height

To understand the above mentioned formulas, watch the following video. It is highly recommended to watch it before you attempt any cone related questions.

What is Area / Surface area / Volume

It is recommended to understand the core concept of area, surface area and volume before we attempt any question based on these concepts.

 

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