Khan Academy: Geometry: Congruent and Similar Triangles

Although a rather complicated topic, this video clearly explains the concept of solving problems involving similar triangles. It employs problem-solving to determine whether two figures are similar triangles. In addition, it provides...

Building on concepts in the first part of the series on similar triangles, installment number two explores how to find the values for given angles in a triangle. These problems are solved by using algebra and ratios. A step-by-step...

Explains how to determine unknown side lengths of similar triangles by identifying corresponding sides and angles ans setting up proportions. The first example is a continuation from the video "Similar Triangles." Practice problems...

Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals. [9:34]

Demonstrates solutions to problems #17-20 of California Geometry released state test questions. Problems address understanding of similar triangles, parallelograms and properties of the diagonals of parallelograms. [11:11]

Explains the difference between congruent triangles and similar triangles. Introduces the idea of scale factors. [9:17]

This video tutorial [12:55] demonstrates solutions to problems #10-14 of California Geometry released state test questions. Problems address understanding of counterexamples, properties of quadrilateral diagonals, and similar triangles.

Explains how to determine unknown side lengths in a diagram that involves similar triangles where the two triangles share a side and the shared side corresponds to two different sides in each triangle. [6:05]

Explains how to determine unknown side lengths in a complex diagram that involves similar triangles. [9:53]

Explains how to identify and use similar triangles in order to determine unknown side lengths in two given diagrams. Each diagram also applies knowledge of angles formed when parallel lines are cut by a transversal. [7:37]