Answer:
33.94 cms of ribbon
Explanation:
Because you need two diagonals to form the x, therefore the amount of ribbon needed is the sum of the distance of both diagonals.
When crossing the diagonal, a rectangular angle is formed, where the diagonal would be the hypotenuse, we know that the distance of the hypotenuse can be calculated by means of the legs, which we know its value (12):
d ^ 2 = a ^ 2 + b ^ 2
a = b = 12
d ^ 2 = 12 ^ 2 + 12 ^ 2
d ^ 2 = 288
d = 288 ^ (1/2)
d = 16.97
16.97 cm is what it measures, a diagonal, therefore tape is needed:
16.97 * 2 = 33.94
A total of 33.94 cms of ribbon is needed