In this section, we delve into the profit maximisation problem for firms operating under perfect competition by employing graphical representations. We begin by understanding that a firm's objective is to produce at an output level where marginal revenue (MR) equals marginal cost (MC). The graphical representation helps in visualising this relationship: the total revenue curve, which demonstrates a straight upward slope due to the constant market price, contrasts against the average cost curves. The area representing profit is highlighted as the difference between total revenue and total cost, facilitating a clearer understanding of how profits change with varying levels of output. We also discuss conditions under which profit maximisation occurs and how graphical analysis aids in determining the optimal output level for firms.