1. segmente a₁ = 1cm
a₂= 2cm = a₁ + 1
a₃= 3cm =a₁ + 1· 2
.............................
a₉₉ = 99cm =a₁ +1· 98 atunci a₆₀= a₁ + 1·59 =1+59 =60
b . a₂₅=a₁ + 1· 24 =25 a₄₈=a₁+1·47 =48
lungimea =Ia₄₈ -a₂₅ I =I a₂₅ - a₄₈ I= 23
sau
2.AB= 2AC-AD
AB=2(AB+BC) _AD
AB=2AB+2BC-AB-BC-CD
2·BC=BD
2 ·BC= 2³³ ⇒ BC=2³²