A protractor is a simple tool used in geometry to measure angles. It typically has a semi-circular shape marked with degrees from 0 to 180. Protractors can be made of plastic or metal and often have a straight edge for drawing lines. They are essential for students and professionals who need to create or analyze angles in various fields, including architecture and engineering. To use a protractor, you align the center point with the vertex of the angle and read the degree measurement where one side of the angle intersects the curved edge. This tool helps ensure accuracy in constructing shapes and understanding geometric concepts.