Similarity
12 videos
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13
Geometry - What is Similarity and Why Does It Matter?
This video explains geometric similarity: shapes with the same form but different sizes. It covers scale factors, corresponding angles, and how similarity differs from congruence.
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Geometry - Similarity and Transformations
Learn what similarity means in geometry: figures are similar when they have the same angles and sides scaled by the same factor using rigid transformations and dilations.
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Geometry - Triangle Similarity Criteria: AA, SSS, and SAS
Learn the three shortcuts to prove triangle similarity: AA (Angle-Angle), SSS (Side-Side-Side ratios), and SAS (Side-Angle-Side with ratios).
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Geometry - Identifying Similar Triangles in Figures
Learn how to identify similar triangles using three key clues: parallel lines, shared angles, and vertical angles. Master the AA similarity principle with clear examples.
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Geometry - Solving for Missing Sides in Similar Triangles
Learn how to find missing side lengths in similar triangles using proportions. Set up ratios of corresponding sides, cross multiply, and solve for the unknown.
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Geometry - Similar Right Triangles: When One Side Plays Two Roles
Learn how an altitude to the hypotenuse creates similar triangles and derive the geometric mean relationship: CD² = AD × DB.
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Geometry - The Angle Bisector Theorem
Learn the Angle Bisector Theorem: how an angle bisector divides the opposite side in the same ratio as the two adjacent sides, with a practical example.
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Geometry - Solving Problems with the Angle Bisector Theorem
Learn the angle bisector theorem: how splitting an angle in half divides the opposite side proportionally to the adjacent sides, with a step-by-step example.
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Geometry - Parallel Lines Divide Triangle Sides Proportionally
Learn how a line parallel to one side of a triangle divides the other two sides proportionally, with a step-by-step example solving for an unknown segment length.
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Geometry - Proving the Pythagorean Theorem with Similar Triangles
Learn an elegant proof of the Pythagorean Theorem using similar triangles created by dropping an altitude from the right angle to the hypotenuse.
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Geometry - Multi-Step Similarity Problems
Learn how to find the crossing height of two strings connecting poles of different heights using similar triangles and proportional reasoning.
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Geometry - Proving Slope Properties with Similar Triangles
Learn why slope is constant on a line using similar triangles, and discover how this proves parallel lines have equal slopes and perpendicular lines have negative reciprocal slopes.