Dmitri's Fire Engines is the sole seller of fire engines in the fictional country of Pyrotania. Initially, Dmitri produced four fire engines, but he has decided to increase production to five fire engines. The following graph shows the demand curve Dmitri faces. As you can see, to sell the additional engine, Dmitri must lower his price from $105,000 to $90,000 per fire engine. Note that although Dmitri gains revenue from the additional engine he sells, he also loses revenue from the initial four engines because he sells them all at the lower price. Use the purple rectangle (diamond symbols) to shade the area representing the revenue lost from the initial four engines by selling at $90,000 rather than $105,000. Then use the green rectangle (triangle symbols) to shade the area representing the revenue gained from selling an additional engine at $90,000.