Imagine a square that measures $$13cm$$ on one side. Calculate the perimeter, area and diagonal.
See development and solution
Development:
The perimeter is the sum of the sides. In the case of a square, all four sides are equal: $$$P=4\cdot13=52 \ cm$$$
The area of the square is: $$$A=13^2=169 \ cm^2$$$
And finally, to calculate the diagonal, we use Pythagoras' theorem: $$$d=\sqrt{l^2+l^2}=\sqrt{2l^2}=\sqrt{2}\cdot l=\sqrt{2}\cdot13=18,4 \ cm$$$
Solution:
$$P=52 \ cm$$
$$A=169 \ cm^2$$
$$d=18,4 \ cm$$