Explanation:
To determine what the height of the ladder reaches up the wall we need to know the height of ladder which is not provided in the question.
So if I assume the height of ladder to be 10ft( just a general assumption)
Then, inclined ladder, wall and distance been the bottom of the ladder and wall will form a right angle triangle.
where height of ladder will be hypotenuse, height of the ladder reaches up the wall will be perpendicular and distance been the bottom of the ladder and wall will be base.
Since, A ladder is inclined at 23 degrees against the wall
⇒ height of the ladder reaches up the wall = Height of ladder×sin23°
= 10ft × sin23° = 3.9073 ft