1 inch = .80 miles. How many inches = 1.00 miles

Question

Hi I am looking for a formula to solve this question. I am a fan of cartography, but failed math. If there are any other formulas that will help me with cartography. I will gladly use them. 

Answer 1

Set up a proportion:

 

1 inch/0.80 miles = x inches/1.00 miles

 

Cross multiply to get 0.80x = 1

 

So,  x = 1/0.80 = 1.25 inches

Answer 2

Hi Joshua, I would look at the problem this way.

 

1 mile is 5280 feet.

 

1 foot is 12 inches.

 

Therefore, there are 12 times 5280 inches in a mile.

 

Inches in a mile = 12 * 5280 = 63360.

 

Conversion of one unit of measure to a different unit of measure is found by identifying the relationship of the result. Here the relationship is inches per mile or inches / mile.

 

To get this:

 

inches / mile = (feet / mile) * (inches / foot)

 

inches / mile = (5280 feet / 1 mile) * (12 inches / 1 foot)

 

We can cancel out the word feet by the word foot (one is plural of the other) leaving:

 

inches / mile = (5280 / 1 mile) * (12 inches / 1) = (5280 * 12 inches) / miles = 63360 inches / mile

 

You can use the same idea for meters to miles, feet to kilometers, or any conversion where we can define the unit of measure.

 

Questions?

 

Answer 3

You can set this up as a conversion fraction.  Since 1 inch is equal to .8 miles, the fraction (1 inch/.80 miles) is equal to 1.  The 'value' is the same on the top as on the bottom.  Multiplying by this fraction (which you can freely do, since multiplying by 1 doesn't change value) can then allow you to change units.

 

Starting from 1.00 miles, we can then multiply:

 

1.00 miles * (1 inch/.80 miles) = 1/.80 inches  (the miles cancel)

1/.80 = 1.25

So 1.25 inches correspond to 1 mile.