Alaterala= Pbazei x h prismei Atotala = Abazei+Alaterala 42 =Abazei +24 Abazei=42-24=18 cm² baza este triunghi echilateral A triunghiului lateral=L²√3/4 L²√3/4=18 L²=18*4/√3=72/√3=72√3/3=24√3 L=√(24√3) P=3*√(24√3) hprisma=Al/P=24/3*√(24√3)=8/(24√3)=8(24√3)/24√3=(24√3)/3√3= =(24√3)*√3/9=24*3/9=8 cm