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Video transcription

Hi, I'm Steve Jones and I'm going to show you how to calculate the volume of a cylinder. First of all, what is a cylinder? A cylinder is a type of prism, it has a circular cross section and a perpendicular height, H. Now even if it's slanted its volume is going to be the same remember, as long as the surface area of the top remains the same, the volume will remain the same, with that same perpendicular height. Now, the volume of this therefore, is the area of the base multiplied by the perpendicular height. The volume is the area of the base, and as we know the area of a circle is pi R squared. So it's pi R squared modified by perpendicular height H. Now we've got an example here, we'll use pi as three to make things simple. We know it's 3.142. The radius of the base here is R two centimeters. The perpendicular height, H, is six centimeters. So let's now put this into the formula. V is equal to pi, here we have pi three times R squared. R times R so R is two, so it's two times two. And finally, the last multiplication, the height H. Six. Okay. So this is three times two, times two, times six, three times two is six, times two is twelve, six twelves, seventy-two. So seventy-two, now this is a volume, so it's going to be centimeters cubed. Remember, check always your units afterwards because if it's a volume it's centimeters cubed, but if it's an area it's only centimeters squared. So this is how you would calculate the volume of a cylinder.