salut!
dupa ce construim figura,ducem AB || EF,EF ∈DC
⇒AB=EF=4
AE=x ⇒ FC=12-4-x=8-x
in Δ ADE-dreptunghic in ∡E
AE²=16-x²
in Δ BFC-dreptunghic in ∡F
BF²=48-(8-x)²=48-64+16x-x²
AE=BF
⇒16-x²=-16+16x-x²
⇒16x=32 ⇒x=2 m
AE²=16-4=12 ⇒AE=2√3
Atrapez=(12+4)*2√3/2=16√3 cm²
