<h2>Answer:</h2>
The height of the flagpole is: 12 ft.
<h2>Step-by-step explanation:</h2>Let the height of the flagpole be: x ft.
Now, we can model this problem with the help of a right angled triangle such that the hypotenuse of the triangle is: 20 feet
and one of the leg of the right triangle is: 16 feet
Now, in order to find the other leg i.e. x we need to use the Pythagorean Theorem.
i.e.
But the height can't be negative.
Hence, we get: