解:∵AD是直径∴∠ABD= 90°∵AD=2*2=4cm,AB=2√3cm∴BD=2cm【勾股定理】∵E为CD中点∴S△AEC=S△AED,S△BEC=S△BED【等底同高】∴四边形ADBC的面积=2S△ABD =2*(1/2*AB*BD) =2*1/2*2√3*2 =4√3(平方厘米)