This document provides information and examples on factoring perfect square trinomials. It defines a perfect square trinomial as a polynomial that can be factored into the square of a binomial. It outlines the criteria for identifying a perfect square trinomial, which are: 1) it must have three terms, 2) the first term must be a perfect square, 3) the third term must be a perfect square, and 4) the middle term must be twice the product of the square roots of the first and last terms. The document provides examples of factoring perfect square trinomials and has students practice identifying and factoring perfect square trinomials.