Which of the following proportions could be used to convert 3,600 feet into miles?

3,600ft/1 mi = 5,280ft/x
x/3,600ft= 5,280ft/1 mi
3,600ft/5,280ft = 1 mi/x
3,600ft/x = 5,280ft/1 mi

1 answer

To convert feet into miles, you need the relationship between feet and miles. There are 5,280 feet in 1 mile.

To find which proportion could be used to convert 3,600 feet into miles, we can rearrange the proportions accordingly.

Here’s a breakdown of each option:

  1. 3,600 ft / 1 mi = 5,280 ft / x: This proportion is incorrect because it implies that 3,600 feet is equivalent to 1 mile, which is not true.

  2. x / 3,600 ft = 5,280 ft / 1 mi: This proportion can be rearranged to find x (the number of miles equivalent to 3,600 feet). It states that the ratio of x miles to 3,600 feet is equal to the ratio of 5,280 feet to 1 mile.

  3. 3,600 ft / 5,280 ft = 1 mi / x: This proportion is also valid. It expresses the ratio of 3,600 feet to 5,280 feet is equal to the ratio of 1 mile to x (the equivalent of 3,600 feet in miles).

  4. 3,600 ft / x = 5,280 ft / 1 mi: This is incorrect as it states that 3,600 feet is equal to some fraction of x miles, which is a misinterpretation of the conversion.

The correct proportions that can be used to convert 3,600 feet to miles are:

  • x / 3,600 ft = 5,280 ft / 1 mi
  • 3,600 ft / 5,280 ft = 1 mi / x

Thus, options 2 and 3 are valid for converting 3,600 feet into miles.