In the figure, the required segment length is 16 units
How to find the length of the segment
The length of the segment is solved using Pythagoras theorem given by the formula
hypotenuse² = opposite² + adjacent²
rearranging
opposite² = hypotenuse² - adjacent²
plugging the values as in the problem
let x be the required distance
x² = 20² - 12²
x² = 400 - 144
x² = 256
x = √256
x = 16