shannon_64
春芽
共回答了13个问题采纳率:100% 举报
设O到AD的距离为h,则 (S⊿AOB + S⊿AOD) / S⊿AOD= AB/h.
(AB-h)/AB =S⊿BOC/S⊿ABC,
S⊿AOB= S⊿DOC=3 ,S⊿BOC=6,
故 (AB-h)/AB =6/(3+6)=2/3,
故 h/AB = 1/3,
故 (S⊿AOB + S⊿AOD) / S⊿AOD= 3,
S⊿AOB / S⊿AOD=2,
S⊿AOD=3/2,
SABCD= 3/2 +3+3+6= 13.5
1年前
4