Help due soon will give brainliest show work

Answer:
D) 13.9 inches
Step-by-step explanation:
use the pythagorean theorem to solve this - a^2 + b^2 = c^2
8.5^2 + 11^2 = c^2
solving gets us a value of 193.25, so next, get the square root of that to the the diagonal length (13.90143...)