On Carrie's map, Greenville and North Valley are 4.5 inches apart, on her map is 1 inch 20 miles. How far is Greenville from North Valley?

1 Answer
smendyka
Jul 29, 2017

See a solution process below:

Explanation:

We can write this as:

#1# inch is to #20# miles as #4.5# inches is to what?

Or

#1" in" -> 20" mi":4.5" in" -> x#

Or

#(1" in")/(20" mi") = (4.5" in")/(x#

To solve this last equation we can first do a cross product or cross multiply the equation:

enter image source here

#1" in" * x = 20" mi" * 4.5 "in"#

#1" in"x = 90" in" * "mi"#

#(1" in"x)/(1" in") = (90" in" * "mi")/(1" in")#

#(color(red)(cancel(color(black)(1" in")))x)/color(red)(cancel(color(black)(1" in"))) = (90color(red)(cancel(color(black)(" in"))) * "mi")/(1color(red)(cancel(color(black)(" in"))))#

#x = (90" mi")/1#

#x = 90" mi"#

Greenville is #color(red)(90)# mile from North Valley.

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