The solution for right triangles is to use the basic trigonometric function:
For this problem, the length of the hypotenuse is given and we are looking for the side opposite, thus we will use sin x.
where
x= 55 degrees
h=25 m
sin x= side opposite/hypotenuse
sin55=sideopposite/25m
25msin55=side opposite
side opposite = 20.5 m