PHYSICAL ann LITERARY. 131 
the arc FH and the chord FH; and there- 
fore the triangle LHE will be equal to the 
fpace contained by the arc FH and the 
chord FH: But, becaufe DL, HE are pa- 
rallel, the triangles DHE, LHE are equal; 
therefore the triangle DHE is equal to 
the fpace contained by the arc FH and 
the chord FH: And, becaufe DF, CH are 
parallel, the triangles CDH, CFH are e- 
qual; therefore the fpace HCDE will be 
equal to the fector CFH. Let the fector 
BCH be added to both, and the fector 
BDE will be equal to the fector BCF: Bat, 
becaufe the fector BCF is greater than the 
feGtor BDH and lefs than the fe@tor BDK; 
therefore the fector BDE is greater than 
the feGtor BDH and lefs than the fector 
BDK ; and therefore DE falls between 
DH, DK: And, becaufe the point D is not 
very excentric, the limiting are HK will 
be little ; therefore the tangent HE may 
be confidered as coinciding with the arc 
FikK, Becaufe the fector BDE is equal to 
bet feGtor BCF, the femicircle will be to 
the fector BDE as the femicircle to the 
Gor BCF:. But the femicircle is to the 
aban 
