Answer:
4

Explanation:
To reduce a radical of a square root, you want to find a perfect square that multiplies into that number. 16 is a perfect square (of 4) and can be divided into 160. so
becomes
x
(because 16 x 10 = 160) then we simplify the square root of 16 to be 4. We leave the square root of 10 because it cannot be simplified.
Hope this helps!
:)