Answer:
The perimeter of a square is 20
if length of the square is x
perimeter of a square = x + x+ x + x = 4x = 20
4x = 20
x= 20/4
x = 5
Let get the length of one of the diagonal is y
According to the Pythagoras low,
y^2 = x^2 + x^2
y^2 = 5^2 + 5^2
y^2 = 25 + 25
y^2 = 50
y= sqrt(50)
Explanation: