The three types of straight lines in haircutting include horizontal, vertical, and which lines?

• A. Diagonal
• B. Curved
• C. Wavy
• D. Angular

Answer: (A)

Straight lines in haircutting have three main orientations: horizontal, vertical, and diagonal. A diagonal line slants across the head, forming an angle, and is still a straight line even though it isn’t horizontal or vertical. Diagonal lines are used to create shape with angles and to build layers or graduation, giving movement and contour to the haircut. The other options describe curved lines (they bend) or refer to sharp corners rather than a distinct straight orientation, so they don’t fit as the third straight-line type.