20 Geometrical hflruSiions 



The general Method of making and ftriking out 

 Pcl3^gonar Figures being thus fixd, I (hall illuftrate 

 and explain it farther by a few Examples, and then 

 leave the Learner to his farther Pra(^ice therein. 



PROPOSITION XIV. 



Upon a Lhte given, to 7nahe a regular Heptagon, or 

 Figure of f even Sides. 



We muft: firfl: luppofe the Line A B defign'd to 

 make an Hexagon of ^ betaufe, as is before inti- 

 mated, the Hexagon is the Figure, kom which all 

 Polygonar Figures aj^c: made. 



After having drawn a Line perpendicular to AB, 

 from the Middle thereof d, fetthe CompafTes iii A 

 or B, and draw the Arch, A C, which divide 

 into fix equal Parts, and fixing the CompafTes in C, 

 extend them to Part 5 ^ from whence you may de- 

 fcribe a little Arch -, or rather transfer that Mea- 

 fure on the middle Line to Letter O, and that is 

 the Center of the Heptagon. Having then de- 

 fcrib'd a Circle, upon that draw the Lines B A F 

 G H I K, which will make feven Sides, equal to 

 the fingle one A B required. Fig. i, 2. 

 On the Ground 



The Practice is the fame, and fo needs no Repeti- 

 tion. Vide Fig. 5- 



PROPOSITION XV, 



Within a Circle given to infcrihe an Heptagon, 

 Draw half the Diameter I A from the End A, 

 and from the Interval A I defcribe the Arch C I C v 

 draw the right Line C C, bear the Half, C O, fe- 

 ven times within the Circumference of the Circle, 

 and you fhall have the Heptagon required, A m 

 d, Bgf e. Vide ¥ig. ?. 



The PraSice on the Ground 

 Is fo near the fame, that for farther Inftruftion 

 I need only refer the Reader to the Scheme, Fig. 6. 



