Primary Industries

Answers - Fencing calculations

Use the scale on the map to calculate the length of the fence.
Length of new fence:
- Western side = 300 m
- Northern side = 250 m
- Eastern side = 350 m
TOTAL LENGTH = 900 m
Determine the number of strainer posts required.
No. strainer posts = 3

1 strainer at each corner and 1 at the new gate.
Determine the number of diagonal stays required.
No. of diagonal stays = 6

2 stays at each corner, 1 at the new gate strainer and 1 stay for the existing strainer post on the eastern side.
Calculate the number of steel posts that will be needed.
No. of steel posts:
- Western side = (300 ÷ 5) - 2 = 58 (allows for gate strainer)
- Northern side = (250 ÷ 5) - 1 = 49
- Eastern side = (350 ÷ 5 ) - 1 = 69
TOTAL NO. STEEL POSTS = 176
Calculate the required length of plain wire. Allow one extra metre to wrap and strain each end of every wire.
Length of plain wire:
- Western side = 300 + 2 - 4 = 298 m (4 m allows for gateway)
- Northern side = 250 + 2 = 252 m
- Eastern side = 350 + 2 = 352 m
TOTAL LENGTH OF PLAIN WIRE = 902 m
Calculate the required length of barbed wire (don't forget to allow one extra metre to wrap and strain each end of every wire).
Length of barbed wire:

TOTAL LENGTH OF BARBED WIRE = Length of plain wire × 4
= 902 × 4
= 3608 m
The barbed wire will be bought in 500 metre rolls. How many rolls of barbed wire are needed to complete the fence?
Rolls of barbed wire:

NO. ROLLS OF BARBED WIRE = 3608 ÷ 500

= 7 full rolls + 216 m = 8 rolls