Triangle Proportionality Theorem Side Splitter

If a line is parallel to one side of a triangle and intersects the other two sides, it divides those sides proportionally! In this video, we take clear, organized notes on the Side Splitter Theorem (also called the Triangle Proportionality Theorem) and learn how to use proportional relationships to solve for missing side lengths in triangles. After building the theorem step-by-step, we work through several practice problems applying proportions to find unknown values. We also cover the Converse of the Triangle Proportionality Theorem and use it to determine whether a line is parallel to a side of a triangle. To finish, we tackle a more challenging application problem where solving the proportion leads to a quadratic equation, combining geometry and algebra skills together. Topics covered in this lesson: • Side Splitter Theorem / Triangle Proportionality Theorem • Writing and solving proportions • Finding missing side lengths • Converse of the Triangle Proportionality Theorem • Parallel lines in triangles • Solving quadratic equations from proportions • Geometry and algebra connections This lesson is great for Geometry students learning similarity, proportional reasoning, and triangle theorems. Thank You for your Support! Patreon: https://www.patreon.com/cw/LinzeyGMath For Practice: https://www.ixl.com/math/geometry/triangle-proportionality-theorem #learnmath #practicemaths #teachmaths #maths #Geometry #MathTutorial #GeometryHelp #HighSchoolMath