We have to calculate the angle in the picture, so we need to use the trygonometric fuctions:
[tex]\begin{gathered} \cos \theta=\frac{adyacent\text{ side}}{hypothenuse} \\ \cos \theta=\frac{13}{20} \\ \theta=\cos ^{-1}(\frac{13}{20})=49^{\circ}27^{\prime}30.23^{\doubleprime}\approx49^{\circ} \end{gathered}[/tex]
The angle is 49°.
