Hi, so you would just use the pythagorean theorem, which I see you're doing. So first calculate 10.30² which is 106.09. Then calculate 4.9² which is 25.01. Now we add them. Which is 130.1. Now we have x², however if you want to find the hypotenuse you need x, not x². So, to undo the ² we have to square root both sides. We now get 11.4061386981. Depending on how you want to round it it can be different but I'm going to round it to the nearest tenth which is 11.4. So, x is approximately 11.4.
