Final answer:
The optimal approach for a sales associate to acquire product knowledge is by attending product demonstrations and doing online research for thorough understanding and hands-on experience with the appliances.
Step-by-step explanation:
The best method for a sales associate to learn the product knowledge needed to sell a new line of appliances is a combination of direct and indirect learning approaches. Attending product demonstrations offered by the manufacturer is highly valuable because it allows the associate to gain first-hand information, ask questions, and take notes on the specifics of the products. Moreover, it would benefit the associate to research the product line on the internet and review any available product information. This can include reading consumer reviews, product descriptions, and technical specifications. While observing the store manager and meeting with experienced sales associates can also be helpful, these methods should complement the direct learning from official resources and hands-on experience with the products.