Question

如图,已知菱形ABCD的边为2cm,∠BAD120°,对角线AC、BD相交于点O,试求这个菱形的两条对角线AC与BD的长

Answer 1

∵菱形ABCD,对角线AC、BD交于点O,AB=2cm

∴AC⊥BD,AC=2AO,BD=2BO,AD平行BC,∠BAO=1/2∠BAD°=60

∴Rt△ABO

∴∠ABO=90°-∠BAO=30°

∴AO=1/2AB=1cm

BO=根号3AO=根号3cm

∴AC=2AO=2cm

BD=2BO=2根号3cm

如有疑问可追问.

望采纳,谢谢!