This educational video provides a comprehensive guide to classifying triangles based on two primary criteria: their angle measures and their side lengths. The narrator, Justin, walks viewers through the fundamental properties of triangles, starting with the Triangle Sum Theorem which states that interior angles always sum to 180 degrees. The video systematically breaks down classification categories including acute, right, obtuse, and equiangular for angles, as well as scalene, isosceles, and equilateral for sides. Key mathematical themes include geometric definitions, theorem application, and algebraic problem-solving within a geometric context. The video introduces and applies the Isosceles Triangle Theorem and its converse to show the relationship between opposite sides and angles. It also incorporates the Pythagorean Theorem to calculate missing side lengths in right triangles, bridging geometry with algebra and arithmetic involving square roots. For educators, this video serves as an excellent instructional tool for middle and high school geometry units. It includes built-in pause points for students to calculate missing values, making it highly interactive. The content moves beyond simple identification by requiring students to solve for variables (x) and use deductive reasoning to determine classifications, making it suitable for introducing new concepts or reviewing for assessments.