 So, we have a circle here and we will divide this circle into few parts and our objective here is to find out the area of the circle or rather visualize the area of the circle and there is a very interesting way in which we can do that. So, I have divided the circle into eight equal parts now. I just want you to focus on one of these parts just color it and if you just look at this pie this resembles a triangle and let me color the other one what I will do is I will arrange these two pies and this is how the two pies when arranged together will look like. Now if I arrange all such pies so if I arrange all the eight pies side by side this is how I will be able to arrange all these eight pies. Now notice one thing the boundary of all these pies together is equal to the circumference of the circle. Now if the radius of this circle is r then this side length is also going to be r now because the circumference of this circle is 2 pi r and the total boundary of the pies also constitutes to be 2 pi r half of it is above half of it is below so then the total length here is going to be pi r and the same thing will be here. With this particular diagram where this looks like a rectangle where one side is r and the other side is pi r how can we make sure that the area of this shape indeed is equal to area of the circle what we do is that we want to divide the circle in more and more parts look what happens when we divide the circle in more and more parts as the number of pies increase there will come a point when this curvature here will reduce and it will seem like it's a straight line as we keep on increasing the number of pies and as we increase this number of pies this length of the radius will also decrease and it will become more and more straighter and so ultimately in the case where we have infinite pies we will be able to approximate the area of a circle by a rectangle of side r and pi r and the area of this rectangle is r times pi r which is pi r square and therefore area of this circle is also pi r square.