Find at least two real life examples that exhibit a type of proportion. Describe

Question

Find at least two real life examples that exhibit a type of proportion.

Describe why each real life example can be solved by a proportion.

Explain each step as you solve each example using a proportion. Post the link to any references you use.

I know this has been answered on here before but please make a new one.

For example, here is one example of proportions used in baseball statistics:

A major league pitcher is often judged on the basis of his earned run average, or ERA. This number represents the average number of earned runs given up by the pitcher per nine innings. An earned run is any run that the opponent scores off a particular pitcher except for runs scored as a result of errors. For instance, if Tim Lincecum gives up three solo homeruns, and then an error causes another run to score, he is only credited with those first three runs that were "his fault."

The earned run average can be calculated using the following formula:

Therefore, if Roy Halladay was charged with 19 earned runs in his first 89 innings pitched, his ERA would be 19 divided by 89, which is .2135, times 9, which is 1.92, a very good number.

Don't forget to multiply by the 9 at the end. By calculating runs/innings you have only figured out earned runs per inning, but you must keep in mind that an ERA is actually earned runs per nine innings, since a regulation game is 9 innings. The number, usually represented with two places after the decimal, shows how many runs the pitcher gives up in an average complete game.

Explanation / Answer

1st Example: A farmer has a rectangular field where the proportion of length to width is 5:3. Also, the perimeter of the field is 160000 meters. We are required to find the dimensions of the field. If we assume the length of the field to be 5x meters , then the width of the field is 3x meters. Now, the perimeter of a rectangle is 2*length+2*width so that the perimeter of the field is 2*5x+2*3x = 10x+6x = 16x. Then 16x = 160000 so that x = 160000/16 = 10000. Then the length of the field is 5*10000 = 50000 meters and the width of the field is 3x = 3*10000 = 30000 meters. We can verify that the perimeter of the field is 2*50000+2*30000 = 100000+60000 = 160000 meters.

2nd Example: Two brothers John and Mike, own adjoining houses. John has finished The size of John’s family is double that of Mike’s so that John requires a bigger overhead water tank when compared to Mike. Both the water tanks are cubical. The water requirements per person are same for the 2 families. Mike’s overhead tank has a side of 10 feet. We are required to determine the side of John’s overhead tank. Now, we know that if x is the side of a cube, then its volume is x3. Thus, the volume of Mike’s overhead tank is 103 = 1000 cubic feet ( about 7480 gallons).Then the volume of John’s overhead tank is 2*1000 = 2000 cubic feet . If the side of this cubical tank is x feet, then x3 = 2000 so that x = (2000)1/3= 12.6 feet.

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