On the blueprint of a house, 38 millimeters represents 6 meters. The length of the living room is 57 millimeters on the blueprint. What is the actual length of the living room?

Question

On the blueprint of a house, 38 millimeters represents 6 meters. The length of the living room is 57 millimeters on the blueprint. What is the actual length of the living room?

Answer 1

The fastest way to solve this problem is to set up ratios and then solve for x using this conversion:

6m/38mm = x/57mm

I set up this problem this way because on the blueprint, 38mm in the blue print represents 6m in real life. That means that 6m is related to 38mm the way that x meters is related to 57mm. Because the relationship between both of these are the same, I can set them equal to each other. I could have placed the blueprint notation (mm) in the numerator, but I chose to place the real life notation (m) in the numerator instead simply to make it faster to solve the problem with cross multiplication.

Pay special attention to the units in this problem. Because the units for the blueprint measurements are the same (mm) and both are located in the denominator on each side of the equation, there is no need to convert as these units will cancel each other out during the solving process, leaving just the units for the real life measurement (m) left over. This means the final answer will be in meters.