Question

ofer 55 puncte si coronita
De la 3 doar b si e va rog nu altele doar b si e.
doar 3 nu 4 cum se vede in imagine.3 b si e

Answer 1

b)ΔABC~ΔADE⇒AD/AB=AE/AC=DE/BC⇔12/9=AE/18=DE/15
luam:12/9=AE/18⇒AE=12×18÷9=24cm;→AE=24cm
          12/9=DE/15⇒DE=12×15÷9=20cm→DE=20cm
            DB=AD-AB=12-9=3cm→DB=3cm
             EC=AE-AC=24-18=6cm→EC=6cm
e)AC=AE+EC=5√3+2√75=5√3+10√3=15√3cm→AC=15√3cm
luam:AD/AB=AE/AC=DE/BC⇒AD/AB=5√3/15√3=1/3=3√3/BC
1/3=3√3/BC⇒BC=3×3√3=9√3cm→BC=9√3cm
AD/AB=1/3 si AD+DB=AB⇒AB=AD+8√3⇒AD/(8√3+AD)=1/3
⇒3AD=8√3+AD⇒AD=4√3cm⇒AB=AD+DB=4√3+8√3=12√3cm