Each of the numbers which are continually doubled beginning from a dyad is even-times even only.
从2开始连续加倍得到的每个数都是偶倍偶数。
从 2 起加倍得 B、C、D：单位、A、B、C、D 成连比例，A=2 为素数；D 仅被 A、B、C 量度（IX.13），且各为偶数，故 D 是仅偶倍偶数。
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For let as many numbers as we please, B, C, D, have been continually doubled beginning from the dyad A; I say that B, C, D are eventimes even only. Now that each of the numbers B, C, D is even-times even is manifest; for it is doubled from a dyad.
设从2开始连续加倍得到任意多个数B、C、D，显然它们都是偶倍偶数，因为它们是从2加倍而来。
I say that it is also even-times even only.
取单位1。由于从1开始连续成比例的数中，紧接1之后的数A是素数，因此A、B、C、D中最大的D不能被A、B、C以外的任何数整除。
For let an unit be set out. Since then as many numbers as we please beginning from an unit are in continued proportion, and the number A after the unit is prime, therefore D, the greatest of the numbers A, B, C, D, will not be measured by any other number except A, B, C.
根据第九卷命题13，D只能被A、B、C中的数整除。
[IX. 13] And each of the numbers A, B, C is even; therefore D is even-times even only.
而A、B、C都是偶数，所以根据第七卷定义8，D是偶倍偶数。