Request a call back

A metal cylindrical disc of base radius 28cm and height 7 cm is melted and recact into a cylindrical block of radius 14 cm .find the length of the cylindrical block.also find the ratio of the total surface area of the cylindrical disc to that of the block.
Asked by Kumaruday291936 | 22 Feb, 2019, 03:50: PM
Volume of cylinder of base radius r and length h = π×r2 × h  cm3
Total Surface area = 2π×r2+2π×r×h = 2πr×(r+h) cm2

Initial volume of metallic cylinder = π×28×28×7  ...........................(1)

after recasting with 14 cm radius and h cm length, volume = π×14×14×h  .......................(2)

since volume given by eqn.(1) and eqn.(2) are same,  length h of cylinder after recasting is given by,  h =
Ratio of total surface area =
Answered by Thiyagarajan K | 22 Feb, 2019, 04:35: PM

## Concept Videos

ICSE 8 - Maths
Asked by jitendra.kumar | 03 Jun, 2023, 11:09: AM
ICSE 8 - Maths
Asked by akd011977 | 17 May, 2023, 07:51: PM
ICSE 8 - Maths
Asked by sharma.sunita88470 | 14 May, 2023, 04:54: PM
ICSE 8 - Maths
Asked by swarup.ghosh21 | 10 May, 2023, 08:53: PM
ICSE 8 - Maths
Asked by swarup.ghosh21 | 10 May, 2023, 08:51: PM
ICSE 8 - Maths
Asked by swarup.ghosh21 | 10 May, 2023, 08:49: PM