1. The problem asks to find the diagonal of a square with side length 5 cm. 2. Recall that the diagonal $d$ of a square with side length $s$ is given by the formula: $$ d = s\sqrt{2} $$ 3. Substitute $s = 5$ cm into the formula: $$ d = 5\sqrt{2} $$ 4. Simplify the expression to get the numerical value: $$ d \approx 5 \times 1.414 = 7.07 \text{ cm} $$ 5. Therefore, the diagonal of the square is approximately 7.07 cm.