Question

B repede dau 17 puncte

Answer 1

Răspuns:

Explicație pas cu pas:

Ducem CE⊥AB   si in Δ dreptunghic BCE  aflam CE=AD=h

si EB  pentru a afla CD

∡ABC=30°   ⇒CE=BC/2=12/2=6cm

EB =BC cos∡ABC=12×√3/2=6√3 cm    CD=AB-EB=8√3-6√3=2√3cm

A trapez=(AB+CD)×AD/2=(8√3+2√3)×6/2=10√3×3=30√3 cm²