Convert the measurement to inches: 1 yard = 36 inches; 36 inches × 3 = 108 inches.
Divide the total number of inches by the number of dresses being trimmed to determine the length of each piece of ribbon: 108 inches ÷ 4 = 27 inches.
Convert the quotient (27 inches) to a fraction of a yard: \(\frac{\mathrm{27} }{\mathrm{36}}\) = 27 ÷ 36 = 75% = \(\frac{\mathrm{3} }{\mathrm{4}}\) of a yard.