Final answer:
Justin is the principal in the scenario where he hires Miguel to sell a baseball glove, with Miguel acting as the agent.
Step-by-step explanation:
Justin, in this scenario, is considered to be the principal because he is the one who has hired Miguel to perform a service on his behalf, which is the sale of a baseball glove. Miguel acts as Justin's agent, carrying out the task of selling the baseball glove for an agreed compensation of $100. In the world of business and contracts, the person who delegates authority to another to perform certain tasks is called the principal, while the one who carries out these tasks is called the agent.