Question

A ladder 15 m long just reaches the top of a vertical wall. If the ladder makes an angle of 60° with the wall, then the height of the wall is

विकल्प

• \[15\sqrt{3}m\]

• \[\frac{15\sqrt{3}}{2}m\]

• \[\frac{15}{2}\]

• 15 m             

Answer 1

Suppose AB is the wall and AC is the ladder.
It is given that, AC = 15 m and \[\angle\]CAB = 60°.

In right ∆ABC,

\[\cos60°= \frac{AB}{AC}\]
\[ \Rightarrow \frac{1}{2} = \frac{AB}{15}\]
\[ \Rightarrow AB = \frac{15}{2} m\] 

Thus, the height of the wall is \[\frac{15}{2}\]