A similarity transformation is a mathematical operation that changes the position, size, or orientation of a geometric figure while preserving its shape. This means that the angles remain the same, and the sides are proportional. Common types of similarity transformations include translations, rotations, and dilations. In the context of geometry, similarity transformations are often used to compare figures or to solve problems involving triangles, polygons, and other shapes. They help in understanding the relationships between different figures and are essential in fields like architecture and engineering where precise measurements and proportions are crucial.