Creating Scale Drawings
Student Summary
If we want to create a scale drawing of a room's floor plan that has the scale “1 inch to 4 feet,” we can divide the actual lengths in the room (in feet) by 4 to find the corresponding lengths (in inches) for our drawing.
Suppose the longest wall is 23 feet long. We should draw a line 5.75 inches long to represent this wall, because 23÷4=5.75.
There is more than one way to express this scale. These three scales are all equivalent, because they represent the same relationship between lengths on a drawing and actual lengths:
- 1 inch to 4 feet
- 21 inch to 2 feet
- 41 inch to 1 foot
Any of these scales can be used to find actual lengths and scaled lengths (lengths on a drawing). For instance, we can tell that, at this scale, an 8-foot long wall should be 2 inches long on the drawing because 41⋅8=2.
The size of a scale drawing is influenced by the choice of scale. For example, here is another scale drawing of the same room using the scale 1 inch to 8 feet.
Notice that this drawing is smaller than the previous one. Since one inch on this drawing represents twice as much actual distance, each side length needs to be only half as long as it was in the first scale drawing.
Visual / Anchor Chart
