<s id="A18-1.10.01">[10] Now, however, we want to find a line, such that the similar solid figures, described according to similarity, above the two lines are in a certain ratio with one another.</s>
<s id="A18-1.10.02">Thus let there be given a line that is in a certain ratio with another line.</s>
<s id="A18-1.10.03">Let us now assume between the two lines two other lines with continuous proportion, the ratio of the first to the fourth equals the ratio of each of the solid figures constructed above the first to the similar solid object/shape described above the second according to similarity.</s>