Question

On a blueprint, a square with 20 meters per side was shown as a square with 12 centimeters per side. how long would a girder appear on the blueprint if the girder is actually 15 meters long?

Answer 1

We know that

the  scale factor on the blueprint is-------> 12 cm/20 m------> 3 cm/5 m

if 3cm on a blueprint-------------> represent 5 m in the actual
 X cm---------------------------------> 15 m
X=15*3/5------>X=9 cm

the answer is
9 cm