If the length of one side of a square is 8 cm, then the length of the diagonal can be found using the Pythagorean theorem, which states that the square of the length of the diagonal of a right triangle is equal to the sum of the squares of the lengths of its two legs.
In a square, the diagonal is the hypotenuse of a right triangle whose legs are the two sides of the square. Since all sides of a square are equal, we can label the length of one side of the square as "a". Therefore, the length of the diagonal "d" can be found as:
d = √(a^2 + a^2) (using Pythagorean theorem)
Substituting the value of "a" as 8 cm, we get:
d = √(8^2 + 8^2)
d = √(64 + 64)
d = √128
d = 8√2 cm (rounded to two decimal places)
Therefore, the length of the diagonal of a square whose side length is 8 cm is approximately 11.31 cm (rounded to two decimal places).