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## Class 7 math (India)

### Course: Class 7 math (India)>Unit 9

Lesson 5: Conversion of units

# Converting area units

Let's learn how to convert between area units like square centimetres, square metres and square kilometres. Created by Aanand Srinivas.

## Video transcript

so convert 10 meter square and write the same area in centimeter square how many centimeters square will it be and you can actually pause the video right now and and try to convert this all you have to do is know how many meters makes one centimeter or in this case how many centimeters makes a meter we know that hundred centimeters is equal to one meter that's all you need to know to solve this problem everywhere you find a meter replace it with 100 centimeters and see what you get now I'm going to try this problem while writing I'm gonna write this as 10 times meter into meter meter times meter that's what this means and now I'm gonna convert my meters into centimeters and how many meters do I have I have meters twice meter into meter so let me do that I'm gonna write 10 and now this meter will become a hundred centimeter or rather maybe let's put it like this this 1 meter is gonna become a hundred centimeters and the same thing is gonna happen to this meter as well that's gonna become another 100 centimeters so have all my units over here so 10 times 100 centimeters in 200 centimeters let me just take all my numbers together 10 times 100 times 100 that's a big number so I'm gonna write 10 times a hundred times another 100 multiplied by centimeters times centimeters you can notice how treating these units the centimeters and meters just along with the numbers and carrying them till the end makes it so that you will not make any mistake so your 10 meter square 10 times meter into meter keeping all of these units brings you to a case where now you have some number into centimeter into centimeter and that's what you want you want the answer in centimeters square so this is 1 0 0 0 1 2 3 4 5 5 zeros centimeter square and how much is that that's one lakh centimeter square so 10 meters squared is 1 lakh centimeter square let's do one more problem convert a thousand centimeter square centimeter square into meter square in metre square and again the only thing I need to know is that hundred centimeters make one meter so I'm gonna write this differently I'm going to write thousand over here into centimeter into centimeter into cm into cm this is actually 1 cm into 1 cm so we don't write that one and now I have to convert this 1 centimeter into meters now I know that one centimeter is equal to 1 by hundredth of a meter which is another way of saying 100 centimeters make one meter so if I use that away I'll get a thousand times this 1 centimeter will become 1 by a hundredth of a meter and then again this 1 centimeter will become 1 by a hundredth of a meter now the reason I know that I must convert my centimeters into meters is that that's what the question asks if the question says kilometres over here or millimeters over here I'll have to do whatever the question asked me to do so in this case it's meters so I have 1 by 100 into 1 by 100 so let's see what that gives me I'm gonna collect all the numbers together in the unit's together so we'll have 100 sorry 1000 divided by 100 divided by 100 divided by one more hundred finally multiplied by meter into meter now I don't care what this number is I'm happy because now I have my units exactly what I want meter into meter so what is this gonna be a thousand divided by 100 and another 100 so one more zero zero so a thousand divided by 10,000 or that's 1 by 10 1 by 10 and the meter square would have come along with me meter squared and meter square so 1/10 of a meter square or 0.1 meter square 0.1 meter square let's do a problem using kilo meter square now and let's say you have to convert to kilo meter square 2 kilo meter square 2 meter square how many meter square would this be and as always as you pause this video and try to solve this on your own you will see that you're doing the same all these problems now let me try this and let's see if you're thinking about it the same way so I'm gonna write 2 times kilo meters squared so that's gonna be kilometres into kilometers I'm gonna use blue for kilometers kilometres into kilometres and let me stick to my old orange 4 meters so let's make this meter squared so 2 times kilometers into kilometers this is basically 1 kilometer into one kilometer now I know I want my answer in meters so I must write down my killer wherever I find kilometers in my question I'll change that to meter and for that I need to know what's the relationship between a kilometer and a meter so I know one kilometer equals a thousand meters a thousand meters so I'm gonna use this over here I'm going to get 2 times 1 kilometer is gonna become into a thousand meters this becomes a thousand meters this is gonna become another thousand meters so let's let's do this again over here let's write this such that we have the numbers together and the unit's together so I have two times thousand and a thousand that's huge thousand times thousand multiplied with meters into meters or meters squared so all my numbers together over here and what's that going to be equal to - one two three four five six six zeros one two three four five six meter square and what is that that's if I've used my commas that's 20 lakh metre square - kilo meter square is 20 lakh metre square