∆ABC isoscel
AB=AC=25cm ,BC=30cm
aria ∆ABC=BC×h/2
h²=AB²-(BC/2)²=25²-15²=400=20²
h=20
aria∆ABC=30×20/2=300cm²
pentru BD sucim triunghiul astfel incat
Aria∆ABC=AC×BD/2=300cm²
a) BD=2×300/25=2×12=24cm
b)aria ∆ABE=BE×AD/2=2BD×AD/2=
24×AD
AD²=AB²-BD²=25²-24²=49=7²
AD=7cm
b)aria∆ABE=24×7=168cm²
