Please help me yo answer this science lesson. It is about sound waves. Which word is used to describe the distance between any point on one wave to the equivalent point on the next wave?

Can someone explain to me how to do this problem ?

In the first law of thermodynamics, triangle e=q-w, what does q stand for

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?