Question

fie triunghiul ABC si D € [ AC ],astfel incit [ AD ]=[ BD ]=[ CD]
Demonstrati ca m (<ABC)=90°

Answer 1

[AD]≡[CD]=>D mijlocul [AC]=>[BD] mediana
[AD]≡[DC]≡[BD]=>BD=AC/2=>(conform reciprocei teoremei medianei)ΔABC dreptunghic in B=>m(<ABC)=90°