22 Like plaine numbers, and like solide numbers, are such,* 1.1 which haue their sides proportionall.
Before he shewed that a plaine number hath two sides, and a solide number three sides. Now he sheweth by this definition which plaine numbers, and which solide numbers are like the one to the other. The likenes of which numbers dependeth altogether of the proportions of the sides of these numbers. So that if the two sides of one plaine number, haue the same proportion the one to the o∣ther, that the two sides of the other plaine number haue the one to the other, then are such two plaine numbers like. For an example 6 and 24 be two plaine numbers, the sides of 6 be 2 and 3, two tymes 3 make 6: the sides of 24 be 4 and 6, foure times 6 makes 24. Againe the same proportion that is betwene 3 and 2 the sides of 6. is also betwene 6 and 4 the sides of 24. Wherfore 24 and 6 be two like plaine and superficiall numbers. And so of other plaine numbers. After the same manner is it in solide num∣bers. If three sides of the one be in like proportion together, as are the three sides of the other, then is the one solide number like to the other. As 24 and 192 be solide numbers, the sides of 24. are 2. 3. and 4, two tymes there taken 4 times are 24. the sides of 192 are 4.6. and 8: for foure tymes 6. 8 times make 192. Againe the proportion of 4 to 3 is sesquitercia, the proportion of 3 to 2 is sesquialtera, which are the proportions of the sides of the one solide number, namely, of 24: the proportion betwene 8 and 6 is sesqu••••ercia, the proportion betwene 6 and 4 is sesquialtera, which are the proportions of the sides of the other solide number, namely, of 191. And they are one and the same with the proportione of the 〈◊〉〈◊〉 of the other wherfore th••se two solide numbers 24 and 192 be like, and so of other solide nūbers.