Explicație pas cu pas:
A) in triunghiul ADB => (T.P) AD² =18² -(6 rad13)²=> AD²=144=>AD=12cm
A ABCD= 18×12=216 cm²
b)DF // EB => T.F.A DO/OB = DF/EB => DF=EB (deoarece DO=OB) => AE=CF
c)DF=EB
DF//EB => DEBF paralelogram
BF=EB => DEBF romb=>
EO _|_ DB
mEOB = m DAB
B unghi comun => BOE~ BAD => BE/BD =BO/BA => BE/6rad13 = 3rad13/18 => BE=13cm => AE=18-13=5cm
