Question

What is the length of a diagonal of a square with a side length of 6?

Answer 1

D = 8.49 

I- - - - - - - - - - - - I
I                          I
I            d            I a
I                          I 
I                          I
I- - - - - - - - - - - - I

Answer 2

By the Pythagorean Theorem:

d^2=x^2+y^2, where x and y are the dimensions of the rectangle, however this is just a square, so x=y=s so

d^2=s^2+s^2

d^2=2s^2, and we are told that s=6 so

d^2=2(6^2)

d^2=2(36)

d=√(2(36))

d=6√2  units

d≈8.49 units (to nearest hundredth of a unit)