Which of the following fittings is used for connecting pipes at an angle?

The fitting used for connecting pipes at an angle is the elbow. Elbow fittings are specifically designed to change the direction of a pipe run, typically at angles of 90 degrees or 45 degrees. This capability allows for the efficient routing of pipe systems in various construction and plumbing applications, enabling connections around obstacles or to create bends in the piping layout.

Other fittings serve different purposes. A reducer is used to connect pipes of different diameters, allowing for a smooth transition from a larger pipe to a smaller one. A cap is used to seal the end of a pipe, effectively stopping the flow of fluid and preventing contaminants from entering. A joint is a more general term that refers to the connection between two pipes, which could involve different types of fittings or connections but does not specify changing direction like an elbow does.