The ground, the building and the line of sight between the ground camera and the top of the building form right triangle with hypotenuse equal to 45 feet and angle adjacent to this hypotenuse and ground - 50°. The building is an opposite leg to the given angle, then you should write sine function:
[tex] \sin 50^{\circ}=\dfrac{height}{45} \\ \\ 0.766=\dfrac{height}{45}\\ \\ height=45\cdot 0.766=34.47 [/tex].
The answer to the nearest tenth of a foot is 34.5 feet
