Ex 11.3, 9 - Chapter 11 Class 9 Surface Areas and Volumes

Last updated at April 16, 2024 by Teachoo

Transcript

Ex 11.3, 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.
Radius of cone = r = /2 = (10.5/2) m = 5.25 m
Height of the cone = h = 3 m
Volume of the cone (heap) = 1/3 r2h
= (1/3 22/7 5.25 5.25 3) m3
= 86.625 m3
We have to find area of canvas required,
i.e., curved surface area of cone
Curved Surface Area of cone = r
We know that
2 = h2 + r2
2 = 32 + (5.25)2
2 = 9 + 27.5625
2 = 36.5625
= 36.5625
= 6.046
Curved surface area of cone = r
= (22/7 5.25 6.046) m2
= 99.756 m2

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.

Hi, it looks like you're using AdBlock :(

Displaying ads are our only source of revenue. To help Teachoo create more content, and view the ad-free version of Teachooo... please purchase Teachoo Black subscription.

Please login to view more pages. It's free :)

Teachoo gives you a better experience when you're logged in. Please login :)

Solve all your doubts with Teachoo Black!

Teachoo answers all your questions if you are a Black user!