Right derived functors are a concept in homological algebra that extend the idea of functors to measure how well a functor behaves with respect to exact sequences. They are constructed from a left exact functor by applying a process that involves taking a projective resolution of an object. This allows us to derive new functors that capture more information about the structure of the objects involved. These derived functors are particularly useful in the study of modules and sheaves, as they help in understanding properties like cohomology. The most common examples include the right derived functors of the Hom functor, denoted as Ext, and the derived functors of the Tensor product, denoted as Tor.