菱形abcd∠DAB与∠ABC互补,∠DAB与∠ABC的度数之比为1:2则 ∠DAB=60,∠ABC=120 因为菱形对角线垂直平分,且平分∠DAB与∠ABC故∠ADB=60,∠DAC=30,菱形ABCD的周长为16cm故ab=bc=cd=ad=4 三角形abd为等边三角形.BD=AB=4...