What tool is used for squaring cut corners and laying out stairs and rafters?

The framing square is specifically designed for tasks that require precise angles and measurements in construction, particularly in framing applications. It features one long arm and one shorter arm, allowing it to form a right angle, which is crucial when squaring cut corners. This design enables the user to easily mark straight lines and measure specific angles necessary for laying out stairs and rafters accurately.

In contrast, a gate valve is used in plumbing systems to control the flow of liquids, making it irrelevant for layout work. A flaring tool is utilized for creating a flared end on pipes or tubing, often in HVAC applications, rather than for framing tasks. A file card is a cleaning tool for files and rasps and does not assist with measurements or cutting. Therefore, the framing square's functionality makes it the ideal tool for squaring corners and laying out important structural elements in carpentry.