Answer:
The answer is D. 4(sqrt(5))
Explanation:
To find this we use the Pythagorean Theorem a^2+b^=c^2
So making 4 = to a, and 8 = to, and x = to, we do
4^2+8^2= 80
Then we take the square root of 80 to find the missing side, which is equal to 4(sqrt(5)
Good luck!