Help please I'm how sure how to solve

Emergency vehicles need to strike a careful balance between drawing attention with sound sirens and protecting the public (as well as EMTs) against hearing loss. According to the CDC, "loud noise above 120 dB can cause immediate harm to your ears." However, an Illinois regulation requires that all ambulance sirens be sufficiently loud to produce a sound intensity level of 100 dB at 50 ft away from the vehicle. 1. The sound wave from an ambulance can't propagate evenly in all directions because it gets reflected upward by the road. Instead, assume that the sound wave propagates evenly in all directions above horizontal, making a hemispherical wavefront. Find a function for the area of this wavefront A(r) in terms of the radius r. 2. Convert the sound intensity level 100 dB into a sound intensity in W/m. 3. Assume that the sound intensity level is 100 dB at 50 feet away from the ambulance. Using the area function. from 1. and your answer to 2., calculate the power of the siren speaker in Watts. Note that one meter is about 3.28 feet