I latura /-----/-----/+2
II latura /-----/-----/+2 / +8 }102
III latura /-----/
2+2+8 = 12
102 - 12 = 90
2+1+2 = 5 segmente egale
90 : 5 = 18 un segment egal
I latura = 18 +18 + 2 = 38 cm
II latura = 38 + 8 = 46 cm
III latura = 18 cm
38 + 46 + 18 = 102 cm