Khan Academy

Lines, line segments, & rays (K-A)

Radius, diameter, circumference & π (K-A)

Specifying planes in three dimensions (K-A)

Surface area using a net: rectangular prism (K-A)

Terms & labels in geometry (K-A)

Angles in a triangle sum to 180° proof (K-A)

Intro to quadrilateral (K-A)

Kites as a geometric shape (K-A)

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

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

Quadrilateral properties (K-A)

Quadrilateral types (K-A)

Sum of interior angles of a polygon (K-A)

Sum of the exterior angles of a polygon (K-A)

Triangle angle challenge problem 2 (K-A)

Triangle angles review (K-A)

Triangle exterior angle example (K-A)

Triangle inequality theorem (K-A)

Worked example: Triangle angles (diagram) (K-A)

Worked example: Triangle angles (intersecting lines) (K-A)

Dilating points (K-A)

Dilating shapes: expanding (K-A)

Dilating shapes: shrinking (K-A)

Dilations and properties (K-A)

Dilations: center (K-A)