This is honestly a pure guess, but I am guessing they want you to find a perfect triangle, and 3,4,5 is the smallest perfect triangle. Considering they also said it was a right triangle, I strongly beleive the answer is 5.
So for this I would set up a ratio. 1/10=x/380 then you cross multiply so 1x380=10x. Then solve the equation so 380/10=x and you get 38in. Hope my explanation helped!
