A scale drawing is a proportional model — use the scale factor to find real dimensions.
A scale drawing represents an actual object with all lengths reduced or enlarged by the same ratio, called the scale factor. To find the actual measurement, multiply the drawing measurement by the scale factor.
A floor plan uses a scale of 1 cm : 3 m. The bedroom measures 4 cm × 5 cm on the plan. Actual dimensions: 4 cm × 3 = 12 m 5 cm × 3 = 15 m Actual room: 12 m × 15 m
Using a scale to find actual measurements:
Remember This!
Scales can be written as a ratio (1:50), a fraction (1/50), or as two measurements (1 cm = 50 km). Always keep the same units consistent on each side.
On a map, 2 inches represents 50 miles. Two cities are 7 inches apart on the map. What is the actual distance?