 We are going to learn about the concept of area and how we can find the area using the unit measurement Let's say I have two shapes like this a shape a and shape b and if I ask which one is larger So you will definitely say that a is larger than b, but how did you come to that particular conclusion? because Area or the region bound by the shape a is greater than the region bound by shape b Most commonly you might have heard about square feet when people around you talk about Lands and all so square feet is a unit of area and there are different units of area square feet and square meters or Square centimeters depending upon the type of shape that you're talking about if you're talking about say land or Some town area square feet is the most appropriate measurement to use square meters is also similar It can also be used for land or Cities to describe the areas of cities and all square centimeter could be used to describe the area of a paper or Clothes, etc. Now, what is this square centimeter? So let's say this is one centimeter and if you draw a square like this you will get an area of One centimeter square and this is nothing but one square centimeter. So if you fill all this area Let me just enclose it and if I fill it up So this pink area becomes one centimeter square And if I say the area of certain region is 20 square centimeters So such 20 squares would be enclosed by that kind of an area Now, let's see how we can compute the area using the grid where every square in the grid Represents a small square unit. So on the left hand side, we see a grid So if I have drawn a square like this Then how many squares are enclosed by the square and we know the answer here We can simply count one two three four five six seven eight and nine and so the area of Square is nine Square units because I have not specified what's this unit is we can simply write nine square units on the left hand side We see another shape. Let's try and calculate the area of that as well Assuming that this one square unit we can write as one square unit And so let's count the number of squares We see that this much are four units then another four units and another four units and then 12 plus 13 14 15 60 so area that we see alongside is 16 square units Now until this point we have seen the regular shapes, but what if we had any regular shape like this? How would we calculate area of such a figure now to do that? We list out full squares exactly half of the squares which are enclosed then more than half I'm just writing more than half which are bounded by the shape and Less than half and then we classify the given number of squares. So let's go back to the figure So I am shading the full squares and I can already see six full squares. This one is also there This is also a full square. This is cut off and I don't see any other full square here So the full number of squares are eight now. What about exactly half squares? Because this is an irregular shape. There is no exactly half square, but we can see many more than half squares So let's shade them in different color Let me just shade them in brown. So this is More than half This is more than half. This is more than half this is as well more than half another one and This is more than half. This is also more than half. This is as well This this this as well. This are all more than half and The number of squares which are bounded more than half are four plus four plus four which has which is 12 again exactly half squares are zero now We want to look at the squares which are filled less than half. So I'm Putting green color over there and anyway, we are going to ignore all of all of these but you just list out So there are eight less than half squares which are bounded The next thing that we do is to write area of all these squares So the area for full square Will be eight square units The half square zero. So it will be zero for more than half squares We consider that their area is full So we will write 12 square units for squares Which are filled more than half and we totally ignore all the area that was contributed by the squares Which were less than half of their area. So in this case, we can write that approximately I would always like to write Approximately as a word So the area is going to be eight full squares plus twelve full squares Assumed for more than half squares and that will be 20 square units This works because we are ignoring the area contributed by less than half squares And this is how we compute the area of any irregular shape using the grid