182 TABLE V. LENGTHS AND BREADTHS WHICH GIVE AN ACRE. 



Ac. Ro. Po. 



From the required quantity of 2f acres =.230 

 Deduct content of irregular portion or off-set=0 35 



225 



Then look in the Table for the length 133 yards ; 



Yd. Ft. In. 



Opposite which stands the width for 1 acre = 36 1 2 

 Set down the same quantity for the other 



acre = . . . . . 36 1 2 



For the 2 roods take half of 1 acre = .1807 

 And for the 5 poles take a sixteenth of the 



half acre = . . . .105 



Width required of the rectangular portion of 

 thefield= . . . . 92 4 



To set off a certain quantity in the form of a triangle, from the 

 side of a field whose boundaries are straight and perpendicular to 

 each other. 



RULE. 1. Since the area of a triangle is equal to half the area of 

 a parallelogram of the same altitude and base, take half the 

 length of the side which you propose to make the perpendicular 

 for the length, and find the width from the Table as formerly ; 

 measure off the width thus found along the adjoining- side, for the 

 ength of the base of the triangle, a straight line from the end of 

 which to the corner of the field or summit of the triangle will be 

 the boundary setting off the quantity required. 



2. The same . result will be obtained by operating with the 

 whole 1 length of the perpendicular, for the length, and finding the 

 width for twice the given quantity to be set off. 



If the field from which it is proposed to set off a certai i 

 quantity in a triangular form, has its boundaries straight, but is 

 not rectangular, let fall a perpendicular from the point which is 

 to be the summit of tfie triangle on the side which is proposed to 

 be the base, the measurement of which perpendicular is to be 

 taken for the length, and used to find the width or base of the 

 triangle, as directed in the case of the rectangular field. 



EXAMPLE. It is required to set off 1 acre, 20 poles, in the 

 form of a triangle, from the side of a field the length of the per- 

 pendicular, from the summit to the base of the triangle, being 

 160 yards. Required the length of the base ? 



By the first method in the Rule, viz., halving the perpendicular 

 for the length. 



Look in the Table for 80 yards, equal half the length of the 

 perpendicular. 



