Khan Academy

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

Relating circumference and area (K-A)

Area of a parallelogram (K-A)

Area of parallelograms-link (K-A)

Finding height of a parallelogram (K-A)

Area of composite shapes (K-A)

Area of kites (K-A)

Area of trapezoids (K-A)

Finding area by rearranging parts (K-A)

Area of a triangle (K-A)

Area of triangles Notes (K-A)

Finding area of triangles (K-A)

Triangle missing side example (K-A)

Area of rectangles review (K-A)

Counting unit squares to find area formula (K-A)

Creating rectangles with a given area 1 (K-A)

Creating rectangles with a given area 2 (K-A)

Finding missing side when given area (K-A)

Measuring area with partial unit squares (K-A)

Measuring rectangles with different unit squares (K-A)

Transitioning from unit squares to area formula (K-A)

Find perimeter by counting unit squares (K-A)

Finding missing side length when given perimeter (K-A)

Finding perimeter when a side length is missing (K-A)

Perimeter of a shape (K-A)