Question #N807

A square has a side length of 8. What is the length of the diagonal of the square?
A. 8\sqrt{2}
B. 16
C. 8\sqrt{3}
D. 64

Correct Answer is: A

The diagonal of a square divides the square into two 45-45-90 right triangles. The ratio of the length of the hypotenuse to the length of a leg in a 45-45-90 right triangle is $\sqrt{2}$:1. Since the side length of the square is 8, the length of the diagonal is $8\sqrt{2}$.