To find the value of x, use the pythagorean theorem, which is shown in this equation.
a^2 + b^2 = c^2
This means the two shorter sides squared added together equals the hypotenuse which is 8 in this case.
Do the equation like this
4^2 + b^2 = 8^2
We don't know what b is equal to and half of eight is 4 because we need to cut the 8 to get one side of the shorter sides
Solve:
4^2 + b^2 = 8^2
16 + b^2 = 64
b^2 = 48
b = √48
D. √48 is your answer