find the missing length!! pls help meee!!! i need to show work and i’m marking brainliest!!!!!!

Answer:don’t know if it’s right but here
Step-by-step explanation: okay so first you need to know is that, that triangle it a 90 degrees so you put 90 degrees minus 45 it will equal to 45 because 45+45= 90 degrees but if the question says put degrees then put it if not then don’t put it.
Hope it helped