in this video we're going to look at how to find the surface area of a cuboid so here's a cuboid and obviously it's got six faces it's got six rectangular faces the front the back the left hand side the right hand side the top and the bottom so to get the surface area of your cuboid what you've got to do is work out the area of all six of the faces and add them up now you may notice that some of them will be the same for instance the top area will be the same as the area the bottom face the area of the left hand face will be the same as there the right hand face and so on okay so let's work out the surface area of this cuboid so for the front the front you've got 3 by 12 so you do 3 times 12 which is equal to 36 centimeters squared the back is going to be the same so it's going to be another 36 centimeters squared the left hand side this side here it's three high and obviously looking at the length it's going to be 10 long okay so it's going to be 3 times 10 so 3 times 10 equals 30 centimeters squared so the left hand face would be 30 centimeters squared the right hand face would be exactly the same so that's another 30 centimeters squared let's now look at the bottom the bottom is 12 by 10 so you're going to do 12 times 10 for the bottom so it's 120 centimeters squared and the top is going to be exactly the same so it's over 120 centimeters squared and then finally what you've got to do is just add them all up if you just add up all those um areas then you get the area because you've got all six faces there you just add them all up and that's the total surface area so we're just going to do 36 plus 36 plus 30 plus 30 plus 120 plus 120 i press equals so the surface area the total surface area of this cuboid is 372 centimeters squared notice the units because of surface area is centimeters squared okay so let's have a look at another cuboid and work out the surface area of it so this time we've got the height is two centimeters the width is three centimeters and the depth is three centimeters so we've got a rectangle on the front a rectangle on the right hand side on the left hand side and a rectangle on the back the top would be three by three so the top's actually going to be a square and the bottom is going to be a square so let's work out the surface area so the area of the front the front is going to be two by three so we're going to do two times three which equals six centimeters squared that's for the front so the back is going to be exactly the same so the back's gonna be six centimeters squared as well the right hand side well the right hand side is three centimeters by two centimeters so that's going to be again two times three uh it's going to be six centimeters squared and the hand side will be exactly the same we're actually worthwhile wrap writing down what you're working on so this is the front this is the back this is the right hand side this is the left hand side and then let's do the top so the top is going to be three by three so three times three equals nine centimeters squared that's the top and then another nine centimeters squared for the bottom that way you can check that you've got all six of these all six of the faces and i just need to add them up so six plus six is 12 18 24 33 42 so the total surface area is 42 centimeters squared