hey guys so in this video we're going to be looking at Perimeter versus area versus volume so I guess the easiest way to start thinking about it is if we start with something like a square uh that's a terrible square but if I draw these lines on the sides it means all of the sides are meant to be the same length so with perimeter and area these are things which refer to two dimensional shapes and volume is something that applies in the three dimensions so I guess first we'll start by just looking at Perimeter then area then we'll move on to volume so this Square here imagine that the sides of the square are 2 m in length so it's a square so all the sides have to be the same length 2 m 2 m and 2 m so if we want to work out the perimeter the perimeter is just the length of the outside of the shape so for our Square it's going to be just the distance around the outside or the distance around what we call the perimeter so to work that out we want to work out the perimeter it's going to be the distance around the outside of the shape so it's a square the first side is going to be 2 m the second side will be 2 m third side will be 2 m and the last side will be 2 m so if we start here and go all the way around going to have 2 m * 4 we can just add them all together and get 8 m so the perimeter is we just start here we walk all the way around the shape get back to where we started that's the perimeter for this Square it's going to be 8 m so the area looks at the space that the shape covers so for this square if we divide it into four equal parts so the space inside of the square we we want to work out exactly how much space this Square covers so if this length is 2 m and we divide it in half then this length here will be 1 M if we divide this side in half that length will be 1 M we can basically just keep doing this so with area we are concerned with the space that the shape covers um so if this side length here is 1 M and this side is 1 M this is going to form a small 1X 1 M Square there'll be uh four of these so one here this is a 1x 1 M Square this is a 1x 1 M square and this is a 1x 1 M Square so area is looking at the space that the shape covers and we usually measure it in a squared unit so me squar but if we want to work out the area we can see that this two M by 2 m Square covers one meter here covers another meter here another one here and another one here so it covers 4 M squared so the units here are the tricky thing so when we go to work out the area of a shape because it's covering a depth or a width and a length it's going to have these squared units so if we just think about it like this the length of the side of the the square is 2 m uh the length of this side is 2 m so if we multiply those two together it's going to give us the area so we have 2 m this way and 2 m this way um so if we multiply them together it will give us 2 * 2 is 4 and then the tricky bit is here we have to multiply the meters together so me * me is going to be me squ so the area of a shape the space it covers for this Square it's 4 M squar so that's perimeter an area and they deal in two Dimensions so there's only a length and a height but there's no depth so what we're going to look at now is we're going to look at some volumes so if I just get rid of this here now I'll leave the square on the left so the square was for two Dimensions now we're going to look the square on the left is in two dimensions and that was fair perimeter and area if we look now at a cube we can kind of demonstrate what volume is so I'm drawing a cube here it's good but it's it's not perfect so say we work with the same 2 m so it's got 2 met sides and because it's a cube we know that all of the sides have to be the exact same length because that's the definition of a cube it's got six sides all of the exact same length and I use these little dashes to indicate that all of the sides are the same length so when we're talking volume we're talking about the amount that a shape can hold inside of it so if we're thinking of a cube the easiest way to think of it is if we were to fill the cube up with say water so I'll draw the cube here if we were to fill this Cube up with say a liquid and we would just pour liquid into this Cube here it would be how much liquid is this Cube actually able to hold so if we just kept filling it and filling it and filling it until it reached the top how much liquid could we say put into the cube and this is going to be a three-dimensional measurement because it measures not only how high the cube is and how I guess wide the cube is but it's also going to be a function of How deep the cube is so volume is is basically the area inside of a cube or the total space that the cube takes up or the shape takes up sorry so easy way to think about it is if you just pour water into something how much water is it going to hold so when we're talking about volume volume again has its own units so with our two-dimensional shapes we had meters and then met squared so with volume because we have this height uh this width and this depth if we want to work out the volume of a shape the volume for a Cube's going to be say 2 m * 2 m * 2 m this is just how we work out the volume of of this Cube then it's going to come out to be 2 m * 2 m * 2 m is 8 and then meters time meters time met met meters met you get meters cubed so when we're talking about volume we deal in these units met cubed so I'll write that down for everyone one more time so we have perimeter we deal in meters it's the area it's the length around the outside we have area which is the space that a shape takes up and it has the units met squared if we're dealing in meters and volume has the units say meters cubed in this example um and volume is the amount of space inside of a shape or the total amount of space that a shape takes up so that's perimeter area and volume and for more videos on uh specific shapes I'll put them out soon thanks guys