If the two rectangles are similar, what is the value of x?
x
9
12
18

We don’t know which one is the hypotenuse. So if we were to plug it into the Pythagorean theorem, we wouldn’t know where to put it. Two possible answers:

8 squared (copy pasting the symbol here is an inconvenience) + b squared = 10 squared which is 6m after solving.

Or you could say 8 squared + 10 squared = c squared. Solving for C would get us 12.8m as our second possibility.