To find the length of the hypotenuse of a right triangle with legs that are both 12 cm long, you can use the Pythagorean theorem:
\[ c = \sqrt{a^2 + b^2} \]
where \( c \) is the length of the hypotenuse, and \( a \) and \( b \) are the lengths of the legs. In this case:
\[ c = \sqrt{12^2 + 12^2} = \sqrt{144 + 144} = \sqrt{288} \]
Calculating \( \sqrt{288} \):
\[ \sqrt{288} \approx 16.97 \]
Therefore, the length of the hypotenuse is approximately 16.97 cm.
So, the correct answer is 16.97.