The street slope is inclined 15º with respect to the horizontal.
The ball has covered a distance of 120 meters over the horizontal, you have to determine the distance that it covered over the slope
First make a diagram of the situation
As you can see the street horizontal and its slope form a right triangle, where the slope is the hypothenuse and the horizontal is one of its legs.
Since we know one angle and its adjacent side, you have to use the trigonometric ratio that relates both with the hypothenuse to calculate the measure of the hypothenuse.
The trigonometric ratio that relates both the adjacent side and the hypothenuse is the cosine
[tex]\cos \theta=\frac{adjacent}{hypothenuse}[/tex]
From this we can calculate the length of the hypothenuse as
[tex]\text{hypothenuse}=\frac{adjacent}{\cos \theta}[/tex]
Replace the expression with the measure of the angle and the side
[tex]\begin{gathered} \text{hypothenuse}=\frac{120}{\cos 15} \\ \text{hypothenuse}=124.23m \end{gathered}[/tex]
The ball will cover 124.23m in the slope
