Brain-Teaser 464

From The Sunday Times, 19th April 1970 [link]

The triangular home meadow at Cowpleasure Farm is bounded West and South by fences running due north and due east from the farmhouse; its other fence forms one side of a square field known as Starvecrow. The south fence of Home Meadow is the shared north boundary of two contiguous square fields, Paddock and Rookery, whose total area is just half that of Starvecrow.

Farmer Nettle has just refenced the whole outer perimeter (i.e. excluding fences common to two fields). He used 146 equal sections of fencing, none of which needed bending or cutting.

He plans to replace the other fences next year using the same type of section.

How many will he need? (Don’t worry about gates; they are incorporated in some of the standard sections).