A scale factor is a number that describes how much a shape or object is enlarged or reduced in size. It is used in mathematics and geometry to create similar figures. For example, if a triangle has a scale factor of 2, each side of the triangle is doubled in length, making it twice as large. Conversely, a scale factor of 0.5 would reduce the triangle to half its original size. In real-life applications, scale factors are important in fields like architecture and engineering. When designing buildings or models, architects use scale factors to ensure that their plans are proportional. For instance, a model of a building might use a scale factor of 1:100, meaning that 1 unit on the model represents 100 units in reality.