急在Rt△ABC中,角C=90°,S△ABC=30,c=13,且a<b,求a,b
1.在Rt△ABC中,角C=90°,S△ABC=30,c=13,且a<b,求a,b
2.△ABC中,角C=90°,AB=4,BC=2根号3,CD⊥AB于D,求AC,CD,BD,AD,S△ABC.