Price Price, P FIGURE 9.6 Deriving Consumer Surplus from the Demand Curve Consumer surplus on each unit sold is the difference between the actual price and what consumers would have been willing to pay FIGURE 9.7 Geometry of Consumer Surplus Consumer surplus is equal to the area under the demand curve and above the price. $12 $10 $9 P1 8 9 10 11 Quantity, O Consider the large country case of an export subsidy on a graph a-dearly show consumer surplus, producers surplus and government loss. b- What is the net effect of tariff on the national welfare? C- How does the cost and benefits of a tariff change