Okay so you would use the formula to find all sides which is: a2+b2=c2(pretend it’s squared, my keyboard isn’t fancy) then you would plug in the sides into the formulado it would be
5.5+x=12(everything is still squared)
After simplifying the exponent you would have:
30.25+x2=144
Now you would simplify each side
X2=4.33
And then cancel out the 2
Then you would get your answer