Brief description: If the level of average revenue is above the average cost, then the firm will make a supernormal profit.

Detailed description: The level of profit is shown on the diagram by the difference between average cost (AC) and average revenue (AR). Where AR is greater than AC then the firm will make a supernormal profit. The gap between AR and AC is the supernormal profit per unit and to get the total profit you need to multiply by the level of output. This area is shown on the diagram.