26 \a 



1 1 1. Force- 'he mid.' 



.lilies to the 



aides: shew that it' they a! 

 inwards or all act outward luilibritnn. 



MS of the forces meet at a point, naim-ly. 

 "t' thr circle which circiunscril- Ami 



1 -.-two n the directions of two forces is tin- supple- 

 ment angle In-tween thr < lint: sides, 'i'hus 



.(sine of the an^le between the other 

 li Art. U> the forces arc in 



POTCM art at t' i'.ar ]n>ints of a t. 



: 'Tp.-ndirulars drawn from thr angular points on the 

 respectively opp .nid the : 



rtional to the sides: shew that the 

 equilibrium. 



It is known that the perpendiculars meet at a point: see 

 Appendix to J:'.-lt',/. Hence by the preceding p. 

 the forces are in equilibrium. 



V. ./IT?*? is a triangle: //. /. K are points in the sides 

 BC, CA, A I \- such that 



/;// 01 AR 



that if forces represented by AH, HI, CA'act at a 



they will be in equilibrium. 



Let />, E, F be the middle points of the sides; and suppose 

 AD, 1 CF to be drawn. 



