Definition
Scale drawing
A scale drawing shows an object with every length changed by the same fixed ratio.
What it means
Imagine shrinking or enlarging with one rule that never changes. If 1 square on the drawing means 2 metres in real life, then 3 squares mean 6 metres and 2 squares mean 4 metres. You cannot use one multiplier for the width and a different multiplier for the height.
Remember it
One scale for every length.
Example
A playground plan uses the scale 1 cm : 3 m. A fence is 6 cm long on the plan. Multiply 6 by 3, so the real fence is 18 m long.
Watch for
A picture that merely looks smaller is not a scale drawing unless one fixed scale links every represented length to the actual length.
Common mix-up
Keep the direction and units clear: drawing to actual may multiply, while actual to drawing uses the inverse scale.
Exact meaning
A scale drawing represents an object or geometric figure so that every drawing length has the same fixed ratio to its corresponding actual length. The stated scale converts between drawing measures and actual measures, and the represented figure keeps the same shape.