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Find the radius of the circular base. Either circle will do since they are the same size. If you already know the radius, you can move on. If you don't know the radius, then you can use a ruler to measure the widest part of the circle and then divide it by 2. This will be more accurate than trying to measure half of the diameter. Let's say that the radius of this cylinder is 1 inch (2.5 cm). Write it down.
If you know the diameter of the circle, just divide it by 2.
If you know the circumference, then you can divide it by 2π to get the radius.
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Calculate the area of the circular base. To do this, just use the formula for finding the area of a circle, A = πr2. Just plug the radius you found into the equation. Here's how to do it:
A = π x 12 =
A = π x 1.
Since π is approximately 3.14 to three digits, you can say that the area of the circular base is 3.14 in.2
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Find the height of the cylinder. If you know the height already, move on. If not, use a ruler to measure it. The height is the distance between the edges of the two bases. Let's say the height of the cylinder is 4 inches (10.2 cm). Write it down.
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Multiply the area of the base by the height. You can think of the volume of the cylinder as the volume of the area of the base being extended throughout the height of the cylinder. Since you know that the area of the base is 3.14 in.2 and that the height is 4 in., you can just multiply the two together to get the volume of the cylinder. 3.14 in.2 x 4 in. = 12.56 in.3 This is your final answer.
Always state your final answer in cubic units because volume is the measure of a three-dimensional space.
