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.
To figure out the perimeter of the square, you can add the lengths of all the sides together, or multiply one side by four, because all the sides are the same length. So if your square has sides 5 centimeters long, the area of the square is 25 square centimeters, and the perimeter of the square is 20 centimeters. Cube.