By how much did total surplus fall when the market became less competitive?

By how much did total surplus fall when the market became less competitive? This is often referred to as the deadweight loss of imperfect competition. Other market failures such as externalities can also cause a deadweight loss. The next module will explore the deadweight loss associated with a tax.
It may help you to draw a graph on scratch paper when answering this question,and recall that the area of a triangle is one half of the product of base times height.