Khan Academy
Rhombus Diagonals, Quadrilaterals, Geometry
Delving into proof that the diagonals of a rhombus are perpendicular to each other, this lecture evaluates the angles and sides of this figure. It would serve as a great test preparation activity.
Khan Academy
Khan Academy: Similar Shapes & Transformations
This video lesson demonstrates how to determine whether given polygons are similar by trying to map one onto the other. The instructor uses angle-preserving transformations in this process.