Interference of Waves Question
Heres the question:
Two towers of a radio station are 4.00 x 10^2 m apart along and east-west line. The towers act essentially as point sources, radiating in phase at a frequency of 1.00 x 10^6 Hz. Radio waves travel at 3.00 x 10^8 m/s.
a) In which directions is the intensity of the radio signal at a maximum for listeners 20k north of the transmitter (but not necessarily directly north of it)?
b) In which directions would you find the intensity at a minimum, north of the transmitter, if the towers were to start transmitting in opposite phase?
I'm kind of stumped on this lol, not even sure where to start. Anyone help me out?