Measure the length and width of the object with a ruler. Alternatively, measure the distance between two points if you are using a map. Write the measurements down on a piece of paper with your pencil.
Convert the measurements you took to the unit of measurement used for the scale factor, if necessary. For example, if you measured the dimensions in centimeters and the scale factor is specified in millimeters, such as "1 mm = 2 feet," multiply each measurement by 10 to convert centimeters to millimeters. Your final calculations will not be accurate if you do not use the same unit of measurement as the scale factor.
Multiply the measurements you took by the scale factor. For example, if your measurements are 10 cm and 12 cm for the length and width, respectively, and the scale factor is 1 cm = 2 feet, multiply the length and width by two. In this example, the length and width of the object in the real world are 20 feet and 24 feet, respectively.