9514 1404 393
Answer:
21.25
Explanation:
The Pythagorean theorem tells you the length of hypotenuse c of a right triangle with legs 'a' and 'b' is ...
c = √(a² +b²)
Here, that means the diagonal length d is ...
d = √(17² +12.75²) = √(289 +162.5625) = √451.5625
d = 21.25 . . . . length of the diagonal