There are a variety of modern definitions of economics, some reflect evolving views of the subject or different views among economists.
So the area of the square is 7 x7 = 49 cm^2 and the perimeter of the square is 7 x 4 = 28 cm. And in example 1 you have a square of side length 8cm and you need to work out the area and perimeter of the square. So the area of the square is 8 x8 = 64 cm^2 and the perimeter of the square is 8 x 4 = 32 cm.
The area of a square or rectangle is determined by multiplying the length times the width: Area = L x W. A rectangular area measuring 80 ft by 60 ft equals 4800 square feet: Area = 80 ft x 60 ft. = 4800 ft2.