IN triunghiul MBC dreptunghic in B notam MB=X BM=2X MC=2RADICAL 5 APLICAM PITAGORA CM LA PUTEREA 2 =MB LA PUTEREA 2 +BC LA PUTEREA 2 2RADICAL 5 LA A DOUA=X LA PUTEREA 2+4X LA PUTEREA A 2 20=5X LA PUTEREA A DOUA X²=4 X=MUCHIE =2 CUBUL ARE 12 MUCHII SUMA MUCHII 12·4=48