Math
posted by Marcus .
How would proportions be used to "scale up" or "scale down" something?
(Not really sure if I even understand what this means. I even read my text and I can't figure this out.)

Let's say that you have a concentrated disinfectant that says that you should mix one cup of disinfectant to one quart of water  but you need one gallon (sixteen cups) of water plus the added disinfectant to make enough of the mixture. Your proportion would be 1 cup of disinfectant to 4 cups of water, since a quart is four cups. Using this ratio, or proportion, you can scale the amount up to what you need: 1/4 = x/16, where x is the amount of disinfectant (which would be 4 cups).
If you need to use less water than the quart, you can use the same ratio to scale down your amount. Let's say that, instead of a quart, you want to use only two cups of water. You would now need: 1/4 = x/2, where x is again the amount of disinfectant (which would now be only 1/2 of a cup). This is how proportions can be used to scale something up or down.
Respond to this Question
Similar Questions

Physics
"A fish hangs from a spring scale supported from the roof of an elevator. If the elevator has an upward acceleration of 1.2m/s^2 and the scale reads 200N, under what circumstances will the scale read 150N? 
physics
a 60kg man is on a steadily rotating Ferris wheel. the man is standing on a bathroom scale and the scale reads 45kg at the top of the wheel. take g=10m/s^2 (a) what does the scale read when the man is at the bottom of the wheel? 
physics
If you stand on a bathroom scale, the spring inside the scale compresses 0.50 mm, and it tells you your weight is 680 N. Now if you jump on the scale from a height of 1.4 m, what does the scale read at its peak? 
physics
The weightless horizontal bar in the figure below is in equilibrium. Scale B reads 4.00 kg (N.B. as you know, the scale should read N, but no one told the manufacturer). The distances in the figure (which is not to scale) are: D1 = … 
physics
If you stand on a bathroom scale, the spring inside the scale compresses 0.50 mm, and it tells you your weight is 760 N. Now if you jump on the scale from a height of 1.0 m, what does the scale read at its peak? 
physics
if I weigh 177 lb on a stationary scale and stand on that same scale inside an elevator going up at an acceleration of 12 ft/s^2 the scale will read 238lbs. if the elevator, still moving upwards, decelerates at the rate of 32 ft/s^2 … 
physics
Water is in the big beaker in the figure on the left. Scale 1 reads 87 Newtons, scale 2 reads 544 newtons, and scale 3 reads 0 newtons. The hanging block has a density of 15 x 10^3 kg/m^3. What does scale 1 read after the block is … 
physics
doing webwork when i came across this question. sure i had it right but apparently im not. The weightless horizontal bar in the figure below is in equilibrium. Scale B reads 4.20 kg (N.B. as you know, the scale should read N, but no … 
Physics
Holding a long rope by its upper end, you lower it onto a scale. The rope has a mass of 0.160 kg per meter of length, and is lowered onto the scale at the constant rate of 1.30 m/s. (1) Calculate thrust. (2) At the instant when the … 
Physics
I'm sorry this is kind of a long question. I've been staring at it for about an hour now and I have no clue where to even start. Thank you so much!!!! A student stands on a bathroom scale in an elevator at rest on the 64th floor of …