This educational video provides a comprehensive review of the Pythagorean Theorem, a fundamental concept in geometry used to find missing side lengths in right triangles. The narrator, Justin, guides viewers through the definitions of key terms like "legs" and "hypotenuse," explains the core formula ($a^2 + b^2 = c^2$), and demonstrates how to correctly identify which sides correspond to which variables. The video is designed as a refresher for students who have seen the concept before but serves equally well as a first-time introduction. The content progresses from basic definitions to practical application, covering Pythagorean triples (like 3-4-5) and solving algebraic equations to find unknown lengths. It includes three distinct examples: checking a Pythagorean triple, finding a missing hypotenuse, and finding a missing leg. The final example introduces a higher-level skill: simplifying square roots (radicals) when the answer is not a perfect square, bridging geometry with algebraic skills. For educators, this video is an excellent tool for reinforcing geometric vocabulary and algebraic manipulation. It specifically addresses common student errors, such as misidentifying the hypotenuse, and provides clear, step-by-step visual modeling of the calculation process. It prepares students for more advanced topics like trigonometry by ensuring they grasp the relationship between the sides of a right triangle.