1.
ΔBAC ∡(ACB)≡∡(DBC) (din ip) (U)
ΔCDB ∡(ABC)≡∡(DCB) (din ip) (U)
[BC]≡[CB] (latura comuna) (L)
ΔBAC≡(deasupra de acel semn scri U.L.U)ΔCDB
[AB]≡[DC] (L)
[AC]≡[BD] (L)
∡BAC≡∡BDC (U)
2.
ΔEAD [AE]≡[BC] (din ip) (L)
ΔCBD [AD]≡[BD] (din ip) (L)
[DE]≡[DC] (din ip) (L)
ΔEAD≡(deasupra de acel semn sci L.L.L)ΔCBD
∡D≡∡D(U)
∡E≡∡C(U)
∡A≡∡B(U)
