过点A作AF⊥CD交CD延长线于F
∵AE⊥BC,CD⊥BC,AF⊥CD
∴矩形AECF
∴∠EAF=∠AEB=∠F=90
∴∠DAE+∠DAF=90
∵∠BAD=90
∴∠DAE+∠BAE=90
∴∠BAE=∠DAF
∵AB=AD
∴△ABE≌△ADF (AAS)
∴AF=AE,S△ABE=S△ADF
∴正方形AECF
∴S正方形AECF=AE²=100
∴S四边形ABCD=S△ABE+S四边形AECD=S△ADF+S四边形AECD=S正方形AECF=100
过点A作AF⊥CD交CD延长线于F
∵AE⊥BC,CD⊥BC,AF⊥CD
∴矩形AECF
∴∠EAF=∠AEB=∠F=90
∴∠DAE+∠DAF=90
∵∠BAD=90
∴∠DAE+∠BAE=90
∴∠BAE=∠DAF
∵AB=AD
∴△ABE≌△ADF (AAS)
∴AF=AE,S△ABE=S△ADF
∴正方形AECF
∴S正方形AECF=AE²=100
∴S四边形ABCD=S△ABE+S四边形AECD=S△ADF+S四边形AECD=S正方形AECF=100