9514 1404 393
Answer:
56.8 in
Step-by-step explanation:
The side length (s) can be found using the Pythagorean theorem. The short leg of the right triangle is 17/2 = 8.5 inches.
8.5^2 + 18^2 = s^2
s = √396.25 ≈ 19.906 . . . inches
Then the perimeter is ...
2 × 19.9 in + 17 in = 56.8 in