RD Sharma Solutions Class 8 Mathematics Solutions for Volume Surface Area Cuboid Cube Exercise 21.2 in Chapter 21 - Volume Surface Area Cuboid Cube

Question 14 Volume Surface Area Cuboid Cube Exercise 21.2

A beam 5 m long and 40 cm wide contains 0.6 cubic metre of wood. How thick is the beam?


Given details are, Length of beam = 5 m

Width of beam = 40 cm = 0.4 m

Volume of wood in beam = 0.6 m3 Let thickness of beam be ‘h’ m

We know that,

Volume = l × b × h h = volume/(l × b)

= 0.6/(5×0.4)

= 0.3m

∴ Thickness of the beam is 0.3m

Video transcript
[Music] hello dear students i'm sunita nye from lido learning and i'm here to help you with the sum which reads a beam 5 meters long and 40 meters wide contains 0.6 cubic meters of wood how thick is the beam so here we have some pictures of wooden beams just to show you they are used in construction of houses etc so the information given to us is that the beam is 5 meters long and 40 centimeters wide we need to know how thick is the beam right so we are concerned here with the volume of the beam right with the volume of wood in the beam so let's write down the formula for that [Music] we have volume of a beam of the beam and you and you will notice it is a rectangular beam right so the volume of a beam which is rectangular or a cuboidal shape right is given by the length into the breadth into the height now these terms can be used interchangeably right and sometimes they can be reverted as thickness or ah yeah or width right so here we have the length is given as 5 meter so 5 meters long the breadth or the width is given as 40 centimeters so let's convert that into meters and write it as 0.4 and we are required to find the height or the thickness in this case all right so let's let's replace height with thickness t okay okay this is given as the volume is given as 0.6 cubic meters right so what will the thickness be the thickness t will be equal to 0.6 divided by the product of 5 and 0.4 right so we can get rid of the decimal point and we can write it as 6 upon 5 into 4. so let's reduce this here we have 3 here we have 2 all right so that is 3 upon 10 which is equal to 0.3 meters so the thickness of the beam is 0.3 meters or 30 centimeters so this is our answer i hope you understood the explanation do visit our channel for more homework solutions and subscribe to it for updates as well thank you
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