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print "Enter an amount: "
amount = gets.to_f
print "Convert it from what(inches, feet, miles, millimeters, centimeters, meters, or kilometers): "
from = gets.chomp
print "To what(same options): "
to = gets.chomp
# Set the values in relation to millimeters
values ={
'millimeters' => 1,
'centimeters' => 10,
'inches' => 25.7,
'feet' => 308.4,
'meters' => 1000,
'kilometers' => 1000000,
'miles' => 1628352
}

total = (values[from] / values[to].to_f) * amount

puts "That would be #{total} #{to}"