Use pythagorean's theorem to solve for missing sides of a right triangle.
a^2 + b^2 = c^2
a = 11
b = 17
c = We don't know yet so I'll call it x
11^2 + 17^2 = c^2
121 + 289 = c^2
410 = c^2
c = √410
c = 20.2
Thus, the answer is B.
Hope this helps, and May the Force Be With You!
-Jabba
