Answer:
D)90
Step-by-step explanation:
First you work out 3^4 which is 81.
Then add 9 to it and it becomes 90.
We can use the Pythagorean theorum
a^2+b^2=c^2
c^2 is the length of the longest side squared
so
6^2 + b^2 = 10^2
36+ b^2 = 100
-36 -36
b^2 = 64
b = 8
b is the same thing as your "x", so x = 8
