I nr /-----/-----/-----/
II nr /------/ + 220 } 2640
III nr /-----/
2640 - 220 = 2420
3+1+1 = 5 segmente egale
2420 : 5 = 484 un segment egal
I nr = 484 x 3 = 1452
II nr = 484 + 220 = 704
III nr = 484
1452 + 704 + 484 = 2640
II varianta :
III nr = a
II nr = a + 220
I nr = 3a
3a + a + 220 + a = 2640
5a = 2640 - 220
5a = 2420
a = 2420 : 5
a = 484
III nr = 484
IInr = 484 + 220 = 704
I nr = 484 x 3 = 1452