Khan Academy on a Stick : Area of Diagonal Generated Triangles of Rectangle are Equal

Khan Academy on a Stick

Perimeter and area of triangles

Perimeter and Area Basics
Triangle Area Proofs
Interesting Perimeter and Area Problems
Area of Diagonal Generated Triangles of Rectangle are Equal
Area of an equilateral triangle
Area of shaded region made from equilateral triangles
Challenging Perimeter Problem

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