## Precalculus (6th Edition) Blitzer

$56^{\circ}$
The trigonometric ratios are as follows: $\sin \theta= \dfrac{opposite}{hypotenuse}$ ; $\cos \theta= \dfrac{Adjacent}{hypotenuse}$ and $\tan \theta= \dfrac{Opposite}{Adjacent}$ Since, the height of the pole= $6$ Then $\tan \theta= \dfrac{6}{4}$ So, $\theta=\tan^{-1} (\dfrac{6}{4}) =56^{\circ}$ Our required answer is (using a calculator): $a = 56^{\circ}$