s=semiperimetrul tr ABC=a+b+c/2=13+14+15/2=21⇒A=√s(s-a)(s-b)(s-c)=√21*8*7*6=√3*7*2³*7*2*3=3*2²*7=84. A=B*H/2⇒84=14*H/2⇒H=84*2/14⇒ H=12⇒FIE AM PERPENDICULAR PE BC. AP⊥(ABC), AM⊥BC, AM INCLUSA IN (ABC), BC INCLUSA IN (ABC)⇒PM⊥BC. FIE TR PAM-dreptunghic⇒potrivit th pitagora PM²=PA²+AM²=256+144=400⇒PM=20