Question

buna ziua! ma poate ajuta cineva la acest ex?​

Answer 1

∆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