You have a right-angled triangle in which the height (the item you want to find) is opposite the known angle. You also know the adjacent length to the angle.
This means you should use the tan function; tan(angle) = opposite/adjacent.
Here: tan(62°) = height/15
Multiply both sides by 15: height = 15*tan(62°) ft
$${\mathtt{height}} = {\mathtt{15}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{62}}^\circ\right)} \Rightarrow {\mathtt{height}} = {\mathtt{28.210\: \!896\: \!980\: \!19}}$$
So height = 28 ft to the nearest foot.