Yes, they are close related, but reptiles tend to have scales and amphibians tend to have smooth skin (mostly on tropical amphibians) and even slimy skin.
Amphibians and avians are the most closely related species to reptiles.
Reptiles
Dinosaurs are more closely related to reptiles than to amphibians. In fact, dinosaurs are classified as reptiles. Amphibians are lower on the evolutionary tree than reptiles. Reptiles developed from amphibians. Amphibians developed from fish.
Neither...They were reptiles. dinosaurs were nether amphibians or mammals they were all reptiles, though they are more closely related to birds.
They are generally considered reptiles, though some think they should have their own class.
Reptiles
Mammals are not closely related to reptiles
Dinosaurs are more closely related to mammals. Both mammals and dinosaurs share a reptilian ancestor that they don't share with amphibians.
Phylum Chordata: Subphylum Cephalochordata and Urochordata along with the subphylum Craniata
Reptiles
The group of fishes most closely related to ancestral amphibians are the lobe-finned fishes, which include the coelacanths and lungfishes. These fishes share certain characteristics with amphibians, such as limbs with digits and lungs or lung-like structures, indicating a close evolutionary relationship.
Snakes and crocodiles because snakes and crocodiles are both reptiles but a frog is an amphibian.