A ladder 10 m in length touches a wall at a height of 5m. The angle made by the ladder with the horizontal is

AC= height of the wall 

AB= length of ladder

$\sin \theta =\frac{AC}{AB}$

$\sin \theta =\frac{5}{10}$

$\sin \theta =\frac{1}{2}=\sin 30°$

$\theta =30°$

Angle made by the ladder with horizontal $=30°$