Question

Se da ABCD-trapez dreptunghic ,,m( <bcd)=30 grade
AB║CD
AB=4cm
BC=12 cm

Sa se afle aria-?

Answer 1

coborim inaltimea BH si obtinem triunghiul dreptunghic BHC
BH=1/2BC
BH=6cm
HC=$\sqrt{BC^2-BH^2}= \sqrt{144-36}=6 \sqrt{3}$
DC=DH+HC=4+6√3
$A= \frac{AB+DC}{2}*BH= \frac{4+4+6 \sqrt{3} }{2}*6 = \frac{8+6 \sqrt{3} }{2}*6=3(8+6 \sqrt{3})cm^2= \\ =6(4+3 \sqrt{3})cm^2$