B/C = K/L because they are similar
The answer is going to be s. The proportions are (short leg/long leg) , and the appropriate long leg for h is s.
Using Pathogorean Theorem.....
40 = the square root of 24^2 + 32^2
40 = the square root of 576 + 1024
40 = the square root of 1600
40 = 40