What a brilliant site you have!!! I love it, especially as it saves me hours and hours of hard work. Others who haven't found your site yet don't know what they are missing!
4.MD.3 – Apply the area and perimeter formulas for rectangles in real world and mathematical problems. For example, find the width of a rectangular room given the area of the flooring and the length, by viewing the area formula as a multiplication equation with an unknown factor.
Samples: Calculating Perimeter Regular Shapes. Challenge puzzle -perimeter. Area. Area in daily use.
Using units of measurement
ACMMG137 – Solve problems involving the comparison of lengths and areas using appropriate units
Samples: Length - using decimals and matching equivalence. Length. Calculating distance in miles tutorial. Length and Money.
7.GM.3 – Use side or edge lengths to find the perimeters and areas of rectangles and parallelograms and the volumes of cuboids, given whole-number dimensions
Samples: Perimeter and Area. Calculating area using a grid. Calculating the Area of Irregular Shapes. Area.