Question

Multumesc anticipat!

Answer 1

vezi atasament......................

Answer 2

BE _|_ DC =>m(E) =90°
In triunghiul BEC m(E) =90° si m(C) =60°=>m(B) =90°-60°=30°
AD=BE = 4√3
=>T <30° EC=BC/2 =>BC=2 EC
In ∆ BEC dr =>TP
BE²+EC²=BC²
(4√3)²+ EC²=(2 EC) ²
48+EC²=4EC²
EC²-4EC²=48
-3EC²=-48
EC²=-48:(-3)
EC²=16
EC=√16
EC=4 cm
AB=DE=8 cm
DC= 8 cm+4 cm =12 cm
BC=2×4 =8 cm
P ABCD = 8+8+12+4√3 =28+4√3=4(7+√3) cm
In ∆ ADC dr =>TP
AD²+DC²=AC²
(4√3)²+12²=AC²
48+144=AC²
AC² =192
AC=√192
AC=8√3 cm
In ∆ DBE dr =>TP
DE²+BE²=DB²
8²+(4√3)²=BD²
64+48=BD²
BD²=112
BD=√112
BD=4√7 cm