Răspuns:
Explicație pas cu pas:
Din ΔABD, BD²=AB²+AD²=(6√3)²+6²=6²·(3+1)=6²·4
Din ΔBDD', dreptunghic in D, ⇒D'D²=D'B²-BD²=20²-6²·4=400-144=256
deci D'D=√256=16cm.
Aria(t)=Aria(l)+2·Aria(b);
Aria(l)=Perimetrul(b)·h=2·(AB+BC)·D'D=2·(6√3+6)·16=2·6·16·(√3 +1)=192(√3+1)cm².
Aria(b)=AB·BC=6√3·6=36√3, deci Aria(t)=192(√3+1)+2·36√3=192√3+192+72√3=264√3+192=24·(11√3 +8) cm²
