Final answer:
To find the measurement of a 10ft couch on a scale drawing using a scale of 1 inch = 10 feet, you would divide the actual size by the unit scale ratio, resulting in a couch that would be represented by a length of 1 inch on the scale drawing.
Step-by-step explanation:
If a couch measures 10ft across in real life, to find its measurement in a scale drawing, we would need a specific scale factor or unit scale. For example, let's use the unit scale '1 inch = 10 feet' as in scale drawings and measurements. To convert the actual size to the scale size, we divide the real measurement by the ratio of the unit scale.
First, write the unit scale as a ratio of 1 inch / 10 feet. Then, to find the scaled measurement, you would perform the following calculation:
Scale Measurement = Actual Measurement / Unit Scale Ratio
Scale Measurement = 10 feet / (10 feet / 1 inch)
Scale Measurement = 10 feet × (1 inch / 10 feet)
Scale Measurement = 10/10
Scale Measurement = 1 inch
Thus, on the scale drawing, the couch would be represented by a length of 1 inch.