Example.
Tetraedrons side supposed, Octaedrons side is ½, √{powerof2}½ his Diameter, vvhose square diuided by 12 bringeth 1/24, the roote being √{powerof2}1/24, is the Oc∣taedrons Axis. Likevvise for Icosaedron the medietie of Tetraedrons side diuided in extreame and meane proportion by the first Probleme, maketh the lesser portion ••/4—√{powerof2}5/16, the square hereof doubled, hath for his roote √{powerof2} vni. 14/8—√{powerof2}180/64, so much is the inscribed Icosaedrons side. Agayne, the difference of Tetraedrons sides medieties Portions diuided by ex∣treame and meane proportion is √{powerof2}20/16—1, the square of halfe this diffe∣rence is 9/16—√{powerof2}80/256, vvhich added to the square of Octaedrons sides me∣dietie, produceth ⅝—√{powerof2}5/16, the roote thereof doubled, is √{powerof2} v. 5/2—√{powerof2}5 the true quātitie of Icosaedrōs dimetiēt. Novv by subtracting 7/12—√{powerof2}45/144 the third parte of Icosaedrons sides square, from ⅝—√{powerof2}5/16, the laste pro∣ducte vvhose roote ye doubled to make the Diameter youre remainder vvil be this number 1/24+√{powerof2}45/144—√{powerof2}5/16, vvhose roote vniuersall is the inscri∣bed Icosaedrons Axis.
The con∣tayning Tetrae∣drons side 1
- ...Tetraedrons
- Diameter. √{powerof2}3/2
- Axis, √{powerof2}1/24
- ...The inscribed Octaedrons
- Syde ½
- Diameter √{powerof2}½
- Axis, √{powerof2}1/24
- ...The cōtayned Icosaedrons
- Syde √{powerof2} vni. 7/4—√{powerof2}45/16
- Diameter √{powerof2} vni. 5/2—√{powerof2}5
- Axis, √{powerof2}1/24.