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.
Calculate the area of an equilateral triangle with a side of 10 cm. The perimeter of an equilateral triangle measures 0.9 dm and its height is 25.95 cm. Calculate the area of the triangle. P = 0.9 dm = 90 cm.