For the most part, it's dependent upon :
a. The fabric width, ie, whether 58 or 60 wide
b. Styling, single or double breasted; whether styling requires additional
pockets, or pockets are large patch pockets, etc,.
From my experience, a suit this size would normally require 4.5 would be sufficient at 60 wide fabric. 5 yards with be a much safer amount. Again, you alway's should consider the suit styling, paying particular attention if you want an assortment of pockets on your jacket, hidden pockets, back patch pockets, flaps, etc,. For future reference, I would alway's consider beginning at 5 yards (at minimum