Economc rent & opportunity cost versus consumer & producer s versus, why, horizontal, economic, triangle

farrukhsadiq

I am wondering why economic rent & opportunity cost are differently calculated than consumer surplus & producer surplus.
page 46.
consumer surplus: upper left triangle from horizontal line of equilibrium and demand curve
producer surplus: lower left triangle from horizontal line of equilibrium and supply curve
page 293:
economic rent: lower left triangle from horizontal line of equilibrium and supply curve
opportunity cost: lower right triangle from supply curve and vertical line of equilibrium
On the abscissa you have in both cases the quantity and on the ordinate in both cases the price (wage rate). So, why can’t you calculate them not in the same why?
What do I miss?
Andreas

trogulj

from the above (your statements)
producer surplus = economic rent , which makes sense conceptually as the producer’s surplus is what he gets to “appropriate” over and above normal profit (zero economic rent). But the two make sense in different contexts, producer surplus in the context of supply and demand analysis, and economic rent in the context of calculations of profit, with quantities, price and costs involved. The former is more conceptual, actually it is strictly! conceptual.
I hope this helps