由：a × 4/3 = b × 3/4 = c × 4/4 = d ÷ 1/4 即有 a × 4/3 = b × 3/4 = c × 4/4 = d × 4 设a × 4/3 = b × 3/4 = c × 4/4 = d × 4 = t 所以有 a = (3/4)t = ( 9/12)t b = (16/12)t c = (12/12)t d = (3/12) t 故有：b > c > a > d
