AD⊥BC ad este inaltime , dar si mediana , ΔABC fiind isoscel
in ΔABD AB=ipotenuza=25cm BD=Cateta=10 cm
AD²=AB²-BD²=25²-10²=(25-10)(25+10)=3×5×5×7 h1=AD=5√21 cm
Aabc=AD×BC/2=20×5√21/2=50√21 cm²
A=h2×AB/2 h2×AB/2=50√21 h2=2×50√21/25=4√21 cm
h3=h2 Δ este isoscel
S=h1++h2+h3=5√21+4√21+4√21=13√21 cm
