1. 45 grade
2,congruente, 90 grade
3. 180 grade
4. reflexivitarea, simetria, tranzitivitatea adica ∡A≡∡A (reflexivitatea) ; ∡A≡∡B⇒ ∡B≡∡A (simetria) si (tranzitivitatea ) ∡ A≡∡B si ∡B≡∡C⇒ ∡A≡∡C.
5. concentrice
6. 100 grade
8. 360 grade
