The PraSlice Part II 



First ObservationV 



T o make this fixteenth Praftice common to all regular 

 Polygones^ even from the Triangle and Square^ to the Fi- 

 gure of twelve Sides^ or the Dodecagone^ you may have 

 Rccourfe to the following Table, where are contained the 

 Angles of the Polygone, and thofe of the Center and 'tis 

 fufficient for the Work, to meafure either one of the Sides of 

 the Polygone, or the Line drawn from its Center to one of 

 its Angles. 



Names of the Po- 

 lygones. 



Triangle 



Square . • . . 

 Pcntagone . 

 Hexagone . 

 Heptagone . 

 Oftogone . 

 Enneagone . 

 Decagone . 

 Endecagone 

 Dodecagone 



Ntmber of Degrees 

 of the Angle of the 

 Polygone. 



60 . 

 90 . 

 108 . 



120 . 



I28y. 

 ■ 



140 , 



H4 • 

 1477. 

 150 . 



Number of Degrees 

 of the Angfeofthe 

 Center. 



120 

 90. 

 72 

 60 



7 



45 

 40 



3^ 

 32^ 



30 



Second Observation* 



With refped: to irregular Polygones, you may make 

 ufe of the Methods taught in this Exercife, either dividing 

 them into Triangles^ from a Point or Center taken in them 

 at Pleafure^ meafuring, with the Protrador, ail the Angles, 

 and^ by the Scale^ all the Radius's drawn to the Angles of 

 the Polygone, fetting off upon the Ground the fame Open- 

 ings of the Angles, and the Lengths found upon the Plan ; 

 <tr elfe, meafuring each Angle of the Polygone with the 

 Protractor, and afterwards its Sides, as was juft now men- 

 tioned above. 



THE 



