4. maketh. 12.
Master. So is it.
Again, if. 5. be assigned for one side of a diametralle nomber, and you obserue the former worke you maie easily finde the other side, and the diameter.
First you see, that the square of 5. is. 25. and it hath no halfe. But. 12. and. 13. are the. 2. nombers nighest his halfe: wherfore. 12. shall bee the second side: and 13. must be the diameter. And the diametralle nōber is. 60.
Likewaies, if. 7. be set for the lesser side, the greater side shall be. 24. and the diameter. 25.
Scholar. Touching this I nede no more instruction: the thyng is so manifeste.
Master. Then shewe your knowledge by an example, or twoo.
And first I appoincte 9 for the lesser side of a diametralle nomber, whereunto I would haue you to assigne the other side, and the diameter, &c.
Scholar. I followe your precepte, and multiplie 9. by it self, whereof commeth. 81. whose halfe is betwene. 40. and. 41. Therfore must. 40. be the other side: and 41. the diameter. And here the diametralle nomber is. 360.
Master. Proue the like: where. 15. is the lesser nomber.
Scholar. 15. multiplied square maketh. 225: whose nighest halfes are. 112. and .113. of whiche the first is the seconde side, and the later is the diameter: and the diametralle nomber is. 1680.
Master. what shall be the other nombers: where 21. is the lesser side?
Scholar. 21. yeldeth in square. 441. whose portions nighest his halfe, are. 220. and. 221: And so appereth their offices, and the diametralle nomber is 4620
Master. So maie you saie that vnto. 27. being the lesser side: the greater side shall be. 364. and the dia-ter
