a) 120cm * (1,2cm)kwadrat * pi =172,8pi=542,6
542,6*0,5 = 261,3
b) 3000cm * (0,1)cm kwadrat * pi = 30pi = 94
94*8,96= 844g
c) 6kwadrat*pi *1m = 36pi
4kwadrat*pi*1m = 16pi
36pi-16pi=20
20*7,8=156
d) 0,1cm kwadrat * pi * 16cm = 0,16cm pi = 0,5
0,5*2,3=1,15