Answer: 19.1 feet.
Explanation:
Draw a right triangle as the one shown attached, where "x" is the height in feet that the top of the ladder will reach.
You need to use the Pythagorean Theorem:
Where "a" is the hypotenuse and "b" and "c" are the legs of the right triangle.
If you solve for one of the legs, you get:
In this case, you can identify that:
Then, you can substitute values into the equation
:
Finally, you must evaluate in order to find the value of "x".
Through this procedure, you get the following result: