# RD Sharma Solutions Class 8 Mathematics Solutions for Volume Surface Area Cuboid Cube Exercise 21.1 in Chapter 21 - Volume Surface Area Cuboid Cube

Question 15 Volume Surface Area Cuboid Cube Exercise 21.1

A cube A has side thrice as long as that of cube B. What is the ratio of the volume of cube A to that of cube B?

Given details are,

Let side of cube B be ‘x’ cm

Then, side of cube A = 3x cm So now,

Ratio = volume of cube A / volume of cube B

= (3x)3 / (x)3

= 27x3/ x3 = 27/1 = 27:1

Video transcript
hello dear student i am sunita nair from leader learning and i am here to help you with this sum which reads a cube a has side thrice as long as that of cube b what is the ratio of the volume of cube a to that of cube b so this is our cube a right and this small cube is our cube b now cube a's side is thrice as long as that of cube b so you can see cube a side is much longer than that of q b and it is thrice as long as that of cube b so let's get down to working the sum with this information in hand so here we have if the side let's take the side of the smaller cube that is side of cube b let it be a right a units ok so what will be the side of cube a then side of cube [Music] capital a would be equal to 3 times this side of cube b right that is 3 into a units now let's calculate the volume of both so volume of cube a is equal to 3 a the whole cube right because volume of a cube is given by the side raised to the power of three or side cubed so this works out to 3a into 3a into 3a so let's multiply the coefficient of a first so 33s or 93s are 27 and a into a into a gives us a cubed right now let's calculate the volume of cube b volume of the small cube right that is cube b is equal to its side raised to the power of 3 that is a raised to the power of 3 which is equal to a cube right now we want to know what is the ratio of the volume of cube a to that of q b so let's write it as a ratio volume of cube a to volume [Music] of cube b this is a way we express a ratio right so let's put in the values now that is 27 a cubed upon a cubed so a cube a cube cancel so we can write this as 27 upon 1 or the ratio is 27 is to 1 [Music] so the ratio of the volume of cube a to the ratio to the volume of cube b i'm sorry is 27 is to 1 [Music] this is our answer [Music] i hope you understood the working do drop in a comment if you have any problem with this visit our channel regularly because we have lot of homework solutions like this and subscribe to it for updates as well thank you
Related Questions

Lido

Courses

Teachers

Book a Demo with us

Syllabus

Maths
CBSE
Maths
ICSE
Science
CBSE

Science
ICSE
English
CBSE
English
ICSE
Coding

Terms & Policies

Selina Question Bank

Maths
Physics
Biology

Allied Question Bank

Chemistry
Connect with us on social media!