如图,BC=5.4,AB=4.5,AC=3,过A作AD⊥BC于D,设CD=X,则B^2-BD^2=AD^2=AC^2-CD^2,20.25-(5.4-X)^2=9-X^2,10.8X=17.91,X≈1.6583,在RTΔABD中,sinB=AD/AB≈0.36851,B≈21.6°,在RTΔACD中,sinC=AD/AC≈0.55277,C≈33.6°,...