Khan Academy

Geometry proof problem: congruent segments (K-A)

Geometry proof problem: midpoint (K-A)

Geometry proof problem: squared circle (K-A)

Centroid & median proof (K-A)

Dividing triangles with medians (K-A)

Exploring medial triangles (K-A)

Median, centroid example (K-A)

Proof: Diagonals of a parallelogram (K-A)

Proof: Opposite angles of a parallelogram (K-A)

Proof: Opposite sides of a parallelogram (K-A)

Proof: Rhombus area (K-A)

Proof: Rhombus diagonals are perpendicular bisectors (K-A)

Proof: The diagonals of a kite are perpendicular (K-A)

Triangle medians & centroids (K-A)

Triangle medians and centroids (2D proof) (K-A)

Dilating shapes: expanding (K-A)

Dilating shapes: shrinking (K-A)

Performing dilations (K-A)

Proof: all circles are similar (K-A)

Similar shapes & transformations (K-A)

Determining similar triangles (K-A)

Intro to triangle similarity (K-A)

Solving similar triangles (K-A)

Solving similar triangles: same side plays different roles (K-A)

Triangle similarity postulates/criteria (K-A)