Which type of line is made up of a series of short and long dashes that are alternately spaced?

The type of line that is made up of a series of short and long dashes that are alternately spaced is known as a centre line. In technical drawings, centre lines serve a specific purpose; they indicate the axis of symmetry of an object or the center of a circle or cylindrical feature. This representation allows for clear visualization of symmetrical elements, which can be essential for manufacturing and assembly processes.

While other line types exist, they have different purposes. A dashed line typically consists of uniform short dashes and does not convey the same information about symmetry. A hidden line is made of short dashes spaced at regular intervals and is used to represent features that are not directly visible but are important for understanding the full geometry of the object. A break line, on the other hand, is usually drawn with a zig-zag pattern and is used to indicate that a portion of the object has been removed or "broken off" in the drawing for clarity.

Understanding the function of each line type helps to interpret engineering drawings accurately and ensures effective communication within the manufacturing and design processes.