Answer: 22 inches
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Work Shown:
(1 inch)/(3.5 miles) = (x inches)/(77 miles)
1/3.5 = x/77
1*77 = 3.5*x ..... cross multiply
77 = 3.5x
3.5x = 77
x = 77/3.5
x = 22
22 inches on paper correspond to 77 miles in real life.