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.
Other answers do make this useful point: A square meter is an area equal to the area of a square with dimensions of length one meter by one meter. If someone asks a question like this in general, then a good answer teaches the error in the question and similar questions, and I hope I have done this.