Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

A solid rectangular block of iron of dimensions 7 cm x 4 cm x 2.75 cm is recast into a cylinder of radius 7 cm. Find the height of the recast cylinder.
Asked by Topperlearning User | 26 Oct, 2017, 11:52: AM
answered-by-expert Expert Answer

Dimensions of the rectangular block are

Length (l) = 7 cm, breadth (b) = 4 cm and height (h) = 2.75 cm

Volume of the rectangular block (V) = lbh = 77 cm3

Radius of recast cylinder (R) = 7 cm

Let H be the height of the recast cylinder and V1 denotes its volume.

begin mathsize 12px style straight V space equals space πR squared straight H straight V subscript 1 space equals space 22 over 7 cross times 7 cross times 7 cross times straight H straight V subscript 1 space equals space 154 straight H space cm cubed end style

Rectangular block is recasted into a cylinder. Therefore volume of the cylinder is equal to the volume of the rectangular block.

begin mathsize 12px style straight V subscript 1 space equals space straight V 154 straight H space cm cubed space equals space 77 space cm cubed straight H space equals space 77 over 154 space cm space equals space 1 half space cm space equals space 0.5 space cm end style

Thus, the height of the recast cylinder is 0.5 cm.

Answered by | 26 Oct, 2017, 01:52: PM

Application Videos

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 9 - Maths
25 The "Caring old people organisation"  needs money to build the old age home which requires 164000 bricks.  Bricks measure 10 cm8 cm 4 cm and cost of brick depends on its volume at the rate of ` 1 per 100 cm3.  It requires 4 cylindrical cans of paint of radius 14 cm and height 30 cm.  The cost of paint is ` 1 per 20 cm3.  How much money is required by organisation ?  If “A company gives the money to organization” then, what common value is depicted by A company and organisation.
Asked by harshsejal.83 | 16 Feb, 2023, 03:36: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
the perimeter of the base of a right circular cylinder is 88 cm and it's height is 10cm then its volume is
Asked by remsindi | 18 Jul, 2021, 06:11: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
From a cylindrical wooden log of length 30 cm and base radius 7 root 2 cm, biggest cuboid of square base is made. Find the volume of wood wasted.
Asked by ayushsuukla987 | 31 Dec, 2020, 10:45: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A cube of copper edge 11cm is melted and formed into a cylindrical wire of diameter 0.5cm. what length of wire will be obtained from the cube
Asked by agentdevil1818 | 03 Mar, 2020, 05:27: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A patient in a hospital is given soup daily in a cylindrical bowl of diameter 7 cm .If the bowl is filled with soup to a height of 4 cm ,how much soup the hospital has to prepare daily to serve 250 patients ?
Asked by Sourabh2002yadav | 13 Nov, 2018, 04:07: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
The circumference of the base of a cylindrical vessel of height 28 cm is 352 cm. Find the amount of water it can hold.
Asked by Topperlearning User | 13 Oct, 2017, 01:47: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A rectangular piece of paper 33 cm long and 16 cm wide is rolled along its breadth to get a cylinder of height 16 cm. Find the volume of the cylinder.
Asked by Topperlearning User | 13 Oct, 2017, 01:52: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A cylindrical vessel of diameter 84 cm and height 18 cm contains milk. This milk is to be filled in cylindrical tumblers of radius 7 cm and height 6 cm. Find the number of tumblers that can be filled with milk.
Asked by Topperlearning User | 13 Oct, 2017, 02:14: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A solid rectangular block of iron of dimensions 7 cm x 4 cm x 2.75 cm is recast into a cylinder of radius 7 cm. Find the height of the recast cylinder.
Asked by Topperlearning User | 26 Oct, 2017, 11:52: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
A cylindrical bucket of diameter 28 cm and height 12 cm is full of water. The water is emptied into a rectangular tub of length 66 cm and breadth 28 cm. Find the height to which water rises in the tub.  
Asked by Topperlearning User | 13 Oct, 2017, 01:56: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Grab Our Exam Special Offer-Enrol now!
×