Respuesta :

Answer:

7.07

Step-by-step explanation:

Length

a square has equal length on each side

hence is the perimeter is 20 it means that :

each side is 20/4 = 5

we can make a diagonal line which create 3 right angled triangles

2 sides of the triangle are 5 , this is the base and the height

to find the length we can make use of the Pythagoras theorem

c^2 = a^2 + b^2

c is the hypotenuse ( the diagonal;)

a and b are the opposite and adjacent

hence :

c^2 = 5 ^2 + 5^2

c^2 = 50

c = [tex]\sqrt{50}[/tex]

c = 7.071

to 3sf

diagonal length  = 7.07