To make a direct comparison we need to use the same units of measurement.
BRACKETS ARE USED TO GROUP THINGS. THEY SURVE NO OTHER PURPOSE.
1 foot has 12 inches
Multiply everything inside the bracket by 6
So 3 inches to 6 feet is the ratio
Which is the same as
3 will divide exactly into both 3 and 72 so simplify the ratio.
3 inches is:
So we have the ratio of
Multiply both by 4