verificam daca BC^2=AB^2+AC^2
a) BC^2= 10^2= 100
AB^2= 6^2= 36
AC^2=8^2= 64
36+64=100 rezulta ∆ ABC dreptunghic in A
b) BC^2= 13^2= 169
AB^2= 5^2= 25
AC^2=12^2= 144
25+144=169 rezulta ∆ ABC dreptunghic in A
c) BC^2= 30^2= 900
AB^2= 18^2= 324
AC^2=24^2= 576
324+576=900 rezulta ∆ ABC dreptunghic in A