What should you do when approaching a roundabout?

When approaching a roundabout, the correct action is to slow down and yield to traffic already in the roundabout. This is essential for maintaining safety and ensuring a smooth flow of traffic. The design of roundabouts is meant to facilitate continuous movement, and yielding to vehicles already in the circle allows for a more efficient navigation of the intersection.

Entering too quickly, as suggested in other answer choices, can create unsafe situations. A stop-and-wait approach, like waiting for a green signal, is not applicable because roundabouts operate on the principle of yielding rather than signal control. Additionally, making a complete stop is unnecessary if the way is clear, as it can disrupt the flow of traffic and create bottlenecks. Remembering to slow down and yield is fundamental for safely navigating a roundabout.