Răspuns:
a)
At=2(6×8+6×10+8×10)=2(48+60+80)=2×188=376
b)
2 1/6=13/6
At=2(4×6+4×13/6+6×13/6)=2(24+52/6+13)=2×(37+26/3)=2×137/3=
=274/3=91,(3)
c)
9,(4)=(94-9)/9=85/9
At=2(85/9×12+85/9×9+12×9)=2(85/3×4+85+108)=
=2(340/3+193)=2(340+579)/3=1838/3≈612,(6) cm²
Explicație pas cu pas:
