Area of Squares and Rectangles:
http://www.khanacademy.org/math/pre-algebra/measurement/area-basics/v/introduction-to-area-and-unit-squares
http://www.khanacademy.org/math/pre-algebra/measurement/area-basics/v/introduction-to-area-and-unit-squares
Area of Parallelograms and Triangles:
Area of Trapezoids:
Area of Irregular or Complex Figures:
Finding Surface Area of Nets:
Nets and 3-Dimensional Figures:
Finding Volume of 3-Dimensional Figures: