Is The valcano of Thera apart of the Ring of Fire?

Answer 1

No. The "ring of fire" is the rim of the Pacific Ocean. Thera is another name for Santorini, which is in Greece, far from the Pacific.

Answer 2

Thera is on the island of Crete in the Mediterranean Sea. The Ring of Fire refers to Volcanoes which circle the disappearing (sliding under surrounding plates and melting) Pacific Plate which is underneath the Pacific Ocean. The plate(s) under the Mediterranean are also disappearing, Same process of subduction but, no, Thera is not part of what is referred to as the Ring of Fire.