Final answer:
Commonly used haircutting elevations include 0 degrees for blunt cuts, 45 degrees for graduated cuts, 90 degrees for layered cuts, and 180 degrees for long layered cuts.
Step-by-step explanation:
The most commonly used elevations in haircutting are 0 degrees, 45 degrees, 90 degrees, and 180 degrees. These angles are used to create various haircuts and styles. The 0-degree elevation is used for a blunt or one-length cut. A 45-degree elevation is often used for graduated or wedge cuts. The 90-degree elevation is standard for a uniformly layered cut, and the 180-degree elevation is used for creating layers that are shorter in the interior and longer towards the perimeter of the hair.