解比例的依据是内项积等于外项积.4/x=5/6, 5x=24, x=4.8.x∶1/2=2/3∶4, 4x=1/2×2/3, x=1/12,1.2/2.5=3/x, 1.2x=2.5×3, x=6.25.6.5∶=3.25∶4, 3.25x=6.5×4, x=8.
