How can one identify and calculate the deadweight loss on a monopoly graph?

To identify and calculate deadweight loss on a monopoly graph, you can look for the area of the triangle between the demand curve, the supply curve, and the monopoly's marginal cost curve. This area represents the loss of economic efficiency due to the monopoly's market power. You can calculate the deadweight loss by finding the area of this triangle using the formula: 0.5 x base x height.