Height of the wall is 27 m.
Explanation:
Let the height of the wall = h
Length of the ladder = 9 m
Angle of elevation = 60°
Ladder rests at 9 m below a vertical wall.
So, length of the wall upto which the ladder rests = h - 9
We know,
Cos Ф = base/ hypotenuse
cos 60° = length of the ladder / height of wall upto which the ladder rests
[tex]\frac{1}{2} = \frac{9}{h - 9}[/tex]
So,
h - 9 = 18
h = 27
Therefore, height of the wall is 27 m
