Answer:
16.703
Explanation:
right angle triangle thus we use puthagoras theorem to find the unknown length.
By converse of pythagoras theorem,
c² = a² + b²
c = √a² + b²
where c is the hypothenuse, a and b can be any 2 side of the right angle triangle
so x = √c² - a² = √ 20² - 11² ≈ 16.703 (or u can use calculator to find the long string of decimals and then round off on your own)