If a cylinder is cut by a plane which is parallel to the opposite planes (of the cylinder) then as the cylinder (is) to the cylinder, so the axis will be to the axis. * For let the cylinder $AD$ have been cut by the plane $GH$ which is parallel to the opposite planes (of the cylinder), $AB$ and $CD$. * And let the plane $GH$ have met the axis at point $K$. * I say that as cylinder $BG$ is to cylinder $GD$, so $EK$ (is) to $KF$.
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