Question 6 - Converting one shape to another - Chapter 12 Class 10 Surface Areas and Volumes

Last updated at May 26, 2023 by Teachoo

Since NCERT Books are changed, we are still changing the name of content in images and videos. It would take some time.

But, we assure you that the question is what you are searching for, and the content is the best -Teachoo Promise. If you have any feedback, please contact us.

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class

Question 6
How many silver coins, 1.75 cm in diameter and of thickness 2 mm, must be melted to form a cuboid of dimensions 5.5 cm 10 cm 3.5 cm?
Number of coins = ( )/( 1 )
Volume of cuboid
Length (l) = 5.5 cm
Breadth (b) = 10 cm
Height (h) = 3.5 cm
Volume of cuboid =
= 5.5 10 3.5
= 192.5 cm3
Volume of 1 coin
Coin is in shape of cylinder with
Diameter = 1.75 cm
Radius = Diamete /2 = 1.75/2 cm= 0.875 cm = 875/1000 cm
Height = 2 mm = 2 1/10 cm = 2/10 cm
Volume of 1 coin = 2
= 22/7 (875/1000)^2 2/10
= 22/7 875/1000 875/1000 0.2
= 0.48125 cm3
Volume of cuboid = 𝑙𝑏ℎ
= 5.5 ×10×3.5
= 192.5 cm3
Volume of 1 coin
Coin is in shape of cylinder with
Diameter = 1.75 cm
Radius = Diamete𝑟/2 = 1.75/2 cm= 0.875 cm = 875/1000 cm
Height = 2 mm = 2 × 1/10 cm = 2/10 cm
Volume of 1 coin = 𝜋𝑟2ℎ
= 22/7×(875/1000)^2× 2/10
= 22/7×875/1000 ×875/1000×0.2
= 0.48125 cm3
Volume of cuboid = 𝑙𝑏ℎ
= 5.5 ×10×3.5
= 192.5 cm3
Volume of 1 coin
Coin is in shape of cylinder with
Diameter = 1.75 cm
Radius = Diamete𝑟/2 = 1.75/2 cm= 0.875 cm = 875/1000 cm
Height = 2 mm = 2 × 1/10 cm = 2/10 cm
Volume of 1 coin = 𝜋𝑟2ℎ
= 22/7×(875/1000)^2× 2/10
= 22/7×875/1000 ×875/1000×0.2
= 0.48125 cm3
Number of coins = ( )/( 1 )
= 192.5/0.48125
= 1925/4.8125
= 19250000/48125
= 400
Hence, number of coins = 400

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 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!