ΔABC-dreptunghic, m(A)=90, m(B)=60, m(C)=?

Răspuns :

mas<C=180- (mas<A+mas<B)=180 -(90+60)=  180-150= 30 grade
m(A)-m(B)=m(C)
90-60=30

(nu-s sigura)