Consider the enlargement of the rectangle. A smaller rectangle with length of x inches and width of three-fifths inch. A larger rectangle with length of 20 inches and width of 12 inches. Use the proportion to find the missing dimension of the original rectangle. 1. Set up the proportion: StartFraction x over three-fifths EndFraction = StartFraction 20 over 12 EndFraction 2. Use cross products: 12(x) = 20(3 5 ) 3. Simplify: 12x = 4. Divide: x =